chore: add priority-overflow change file for the opt-out deferral

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: bsunderhus

change/@fluentui-priority-overflow-pr4-opt-out.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "fix: apply a forceUpdate requested before observe once observation begins",
+  "packageName": "@fluentui/priority-overflow",
+  "email": "bsunderhus@microsoft.com",
+  "dependentChangeType": "patch"
+}