ci: Revert to guarding the snapshot upload on an empty auth token

Author: markushi

.github/workflows/build.yml

@@ -49,9 +49,12 @@ jobs:
         uses: getsentry/action-setup-cli@70d7e587b84c2e78cf4d37cd33d7b74fb3729c1b # v1
 
       - name: Upload Snapshots to Sentry
-        # Skip on PRs from forks and from Dependabot, which don't have access to the upload secret
-        if: ${{ github.event_name != 'pull_request' || (github.event.pull_request.head.repo.full_name == github.repository && github.actor != 'dependabot[bot]') }}
         run: |
+          # PRs from forks and Dependabot PRs have no access to the upload secret
+          if [ -z "$SENTRY_AUTH_TOKEN" ]; then
+            echo "SENTRY_AUTH_TOKEN is not available, skipping snapshot upload"
+            exit 0
+          fi
           sentry-cli snapshots upload ./sentry-android-core/build/test-snapshots \
             --app-id sentry-android-core
         env: