fix(flagd): skip helm-install-test when API token secret is unavailable

Gates the helm-install-test job so it skips rather than fails on fork PRs
where REPLICATED_PLATFORM_EXAMPLES_TOKEN is not accessible.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kriscoleman

.github/workflows/flagd-ci.yml

@@ -58,6 +58,7 @@ jobs:
   helm-install-test:
     runs-on: ubuntu-22.04
     needs: [lint-and-template]
+    if: ${{ secrets.REPLICATED_PLATFORM_EXAMPLES_TOKEN != '' }}
     defaults:
       run:
         working-directory: applications/flagd