Fixes mx_MLocationBody_markerBorder (#8069)

Fixes element-hq/element-web#21444

This commit fixes the position of the avatar on the location pin on the
timeline.

Signed-off-by: Suguru Hirahara <luixxiul@users.noreply.github.com>

res/css/views/messages/_MLocationBody.scss

@@ -27,12 +27,17 @@ limitations under the License.
         width: 31px;
         height: 31px;
         border-radius: 50%;
-        background-color: $accent;
         filter: drop-shadow(0px 3px 5px rgba(0, 0, 0, 0.2));
+        background-color: $accent;
+
+        // See _LocationPicker.scss
+        display: flex;
+        justify-content: center;
+        align-items: center;
 
         .mx_BaseAvatar {
-            margin-top: 2px;
-            margin-left: 2px;
+            margin: 0;
+            line-height: 1;
         }
     }