Update PR approval comment to include schema metadata verification (#28679)

Add a reminder for schema-related changes to verify that new or updated
types and properties are visible in the applicable metadata endpoint
(beta or v1.0) before merging.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: FaithOmbongi

.github/policies/resourceManagement.yml

@@ -127,6 +127,9 @@ configuration:
             When the updates in this PR are ready for external customers to use, please replace the **do not merge** label with **ready to merge**.
 
 
+            If this PR includes schema-related changes, verify that the updates are visible in the metadata endpoint before merging: [https://graph.microsoft.com/beta/$metadata](https://graph.microsoft.com/beta/$metadata) for `beta` changes, or [https://graph.microsoft.com/v1.0/$metadata](https://graph.microsoft.com/v1.0/$metadata) for `v1.0` changes.
+
+
             Check the content review workflow [here](https://eng.ms/cid/27dee76c-3a60-4e65-8fdf-08ea849b3498/fid/3a993b6c9d547e46f59d8d7851f191c38bbbea6ead01253dc62fcdd8101a1ff9).
       - removeLabel:
           label: content review in progress