ci: gate RelativeCI job on successful build runs

Author: nperez0111

.github/workflows/relative-ci.yaml

@@ -15,6 +15,7 @@ permissions:
 jobs:
   build:
     runs-on: ubuntu-latest
+    if: github.event.workflow_run.conclusion == 'success'
     steps:
       - name: Send bundle stats and build information to RelativeCI (editor)
         uses: relative-ci/agent-action@fcf45416581928e8dd62eded78ce98c78e5149f8 # v3.2.3