[CI] Fix LauchDarkly References Action triggering on forks (#189232)

## Summary

This action is triggering on pushes to `main` on forks as well, this PR
skips the action on forks. The action will fail on the fork and notify
the developer.

### Testing
Failure on my fork's `main` before this PR
1010067456

Tested with this branch in my fork and it skipped properly
96e2ed6e60
1010151467

Flipped the flag to ensure it's working
2a586ccd73
1010153452

.github/workflows/launchdarkly-code-references.yml

@@ -13,13 +13,14 @@ concurrency:
 jobs:
   launchDarklyCodeReferences:
     name: LaunchDarkly Code References
+    if: github.event.repository.fork == false
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
-      with:
-        fetch-depth: 11 # This value must be set if the lookback configuration option is not disabled for find-code-references. Read more: https://github.com/launchdarkly/ld-find-code-refs#searching-for-unused-flags-extinctions
-    - name: LaunchDarkly Code References
-      uses: launchdarkly/find-code-references@v2.12.0
-      with:
-        accessToken: ${{ secrets.LD_ACCESS_TOKEN }}
-        projKey: ${{ secrets.LD_PROJECT_KEY }}
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 11 # This value must be set if the lookback configuration option is not disabled for find-code-references. Read more: https://github.com/launchdarkly/ld-find-code-refs#searching-for-unused-flags-extinctions
+      - name: LaunchDarkly Code References
+        uses: launchdarkly/find-code-references@v2.12.0
+        with:
+          accessToken: ${{ secrets.LD_ACCESS_TOKEN }}
+          projKey: ${{ secrets.LD_PROJECT_KEY }}