[k8sclusterreceiver] refactor state metrics to use empty units (#27091)

**Description:** 

Change k8s.container.ready, k8s.pod.phase, k8s.pod.status_reason,
k8s.namespace.phase units to empty

**Link to tracking Issue:** #10553

.chloggen/k8sclusterreceiver-empty-units.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: k8sclusterreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "change k8s.container.ready, k8s.pod.phase, k8s.pod.status_reason, k8s.namespace.phase units to empty"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [10553]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/k8sclusterreceiver/documentation.md

@@ -66,7 +66,7 @@ Whether a container has passed its readiness probe (0 for no, 1 for yes)
 
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
-| 1 | Gauge | Int |
+|  | Gauge | Int |
 
 ### k8s.container.restarts
 
@@ -226,15 +226,15 @@ The current phase of namespaces (1 for active and 0 for terminating)
 
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
-| 1 | Gauge | Int |
+|  | Gauge | Int |
 
 ### k8s.pod.phase
 
 Current phase of the pod (1 - Pending, 2 - Running, 3 - Succeeded, 4 - Failed, 5 - Unknown)
 
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
-| 1 | Gauge | Int |
+|  | Gauge | Int |
 
 ### k8s.replicaset.available
 
@@ -402,7 +402,7 @@ Current status reason of the pod (1 - Evicted, 2 - NodeAffinity, 3 - NodeLost, 4
 
 | Unit | Metric Type | Value Type |
 | ---- | ----------- | ---------- |
-| 1 | Gauge | Int |
+|  | Gauge | Int |
 
 ## Resource Attributes
 

receiver/k8sclusterreceiver/internal/namespace/testdata/expected.yaml

@@ -18,7 +18,7 @@ resourceMetrics:
               dataPoints:
                 - asInt: "0"
             name: k8s.namespace.phase
-            unit: "1"
+            unit: ""
         scope:
           name: otelcol/k8sclusterreceiver
           version: latest

receiver/k8sclusterreceiver/internal/pod/testdata/expected.yaml

@@ -24,7 +24,7 @@ resourceMetrics:
               dataPoints:
                 - asInt: "3"
             name: k8s.pod.phase
-            unit: "1"
+            unit: ""
         scope:
           name: otelcol/k8sclusterreceiver
           version: latest
@@ -71,7 +71,7 @@ resourceMetrics:
               dataPoints:
                 - asInt: "1"
             name: k8s.container.ready
-            unit: "1"
+            unit: ""
           - description: Resource requested for the container. See https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.23/#resourcerequirements-v1-core for details
             gauge:
               dataPoints:

receiver/k8sclusterreceiver/internal/pod/testdata/expected_evicted.yaml

@@ -24,13 +24,13 @@ resourceMetrics:
               dataPoints:
                 - asInt: "4"
             name: k8s.pod.phase
-            unit: "1"
+            unit: ""
           - description: Current status reason of the pod (1 - Evicted, 2 - NodeAffinity, 3 - NodeLost, 4 - Shutdown, 5 - UnexpectedAdmissionError, 6 - Unknown)
             gauge:
               dataPoints:
                 - asInt: "1"
             name: k8s.pod.status_reason
-            unit: "1"
+            unit: ""
         scope:
           name: otelcol/k8sclusterreceiver
           version: latest
@@ -77,7 +77,7 @@ resourceMetrics:
               dataPoints:
                 - asInt: "1"
             name: k8s.container.ready
-            unit: "1"
+            unit: ""
           - description: Resource requested for the container. See https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.23/#resourcerequirements-v1-core for details
             gauge:
               dataPoints:

receiver/k8sclusterreceiver/metadata.yaml

@@ -245,20 +245,20 @@ metrics:
   k8s.container.ready:
     enabled: true
     description: Whether a container has passed its readiness probe (0 for no, 1 for yes)
-    unit: 1
+    unit: ""
     gauge:
       value_type: int
 
   k8s.pod.phase:
     enabled: true
     description: Current phase of the pod (1 - Pending, 2 - Running, 3 - Succeeded, 4 - Failed, 5 - Unknown)
-    unit: 1
+    unit: ""
     gauge:
       value_type: int
   k8s.pod.status_reason:
     enabled: false
     description: Current status reason of the pod (1 - Evicted, 2 - NodeAffinity, 3 - NodeLost, 4 - Shutdown, 5 - UnexpectedAdmissionError, 6 - Unknown)
-    unit: 1
+    unit: ""
     gauge:
       value_type: int
 
@@ -369,7 +369,7 @@ metrics:
   k8s.namespace.phase:
     enabled: true
     description: The current phase of namespaces (1 for active and 0 for terminating)
-    unit: 1
+    unit: ""
     gauge:
       value_type: int