feat: create span question from SDK

[frascuchon]

Description

This PR introduces support for configuring feedback datasets with span questions. A new SpanQuestion class is defined for that. The creation workflow would be as follows:

dataset = rg.FeedbackDataset(
   fields = [rg.TextField(name="text"),...],
   questions=[rg.SpanQuestion(name="spans", title="This is the Span question", labels=["person", "org"])],
)

## You can also create label options with a different text that will shown in the annotation UI
rg.SpanQuestion(
   name="spans", 
   title="This is the Span question", 
   labels=[
      rg.SpanLabelOption(value="person", text="Person"), 
      rg.SpanLabelOption(
         value="org", 
         text="Organization", 
         description="This is a description for label org which could be useful as contextual help from the UI"
      )
   ]
)

Closes #4616

Type of change

(Please delete options that are not relevant. Remember to title the PR according to the type of change)

• New feature (non-breaking change which adds functionality)
• Refactor (change restructuring the codebase without changing functionality)
• Improvement (change adding some improvement to an existing functionality)

How Has This Been Tested

(Please describe the tests that you ran to verify your changes. And ideally, reference tests)

Tested locally using a running instance of the Argilla server.

Checklist

• I added relevant documentation
• I followed the style guidelines of this project
• I did a self-review of my code
• I made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I filled out the contributor form (see text above)
• I have added relevant notes to the CHANGELOG.md file (See https://keepachangelog.com/)

[frascuchon]

@nataliaElv I've included you as a reviewer to validate the creation workflow. Let me know if you miss something.

@burtenshaw I've included you to look at the development flow for the current SDK.

[github-actions]

The URL of the deployed environment for this PR is https://argilla-quickstart-pr-4617-ki24f765kq-no.a.run.app

[codecov]

Codecov Report

Attention: Patch coverage is 97.87234% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 89.06%. Comparing base (254f719) to head (7d6bb0c).

Files	Patch %	Lines
src/argilla/client/feedback/schemas/enums.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@                       Coverage Diff                        @@
##           feat/span-questions-support    #4617       +/-   ##
================================================================
+ Coverage                        45.26%   89.06%   +43.80%     
================================================================
  Files                              190      190               
  Lines                            11671    11700       +29     
================================================================
+ Hits                              5283    10421     +5138     
+ Misses                            6388     1279     -5109     

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[jfcalvo]

Looks like there is a failing integration test related with span and a dataset deletion (probably because the dataset was not created well?)