fix(ci): stop skipping unified tests on merge to main (#1083)

The gate job only runs on `pull_request: labeled`, so it is skipped on
push. A skipped ancestor propagates down the needs chain unless a job
opts out, which `unified-tests` never did — so the suite has been
skipped on every merge to main while still burning a Fly machine.

.github/workflows/unified-tests.yml

@@ -57,7 +57,10 @@ jobs:
     name: Run Unified Tests
     runs-on: ${{ fromJSON(format('[{0}]', needs.start-runner.outputs.runner-labels)) }}
     needs: start-runner
-    if: needs.start-runner.outputs.runner-ready == 'true'
+    # !cancelled() so this doesn't inherit gate's skip on push events.
+    if: >-
+      !cancelled() &&
+      needs.start-runner.outputs.runner-ready == 'true'
     timeout-minutes: 90
     environment: unified-tests
     permissions: