[CI] Do not build helpers if no corresponding files changed

.gitea/workflows/build-helpers.yml

@@ -1,6 +1,9 @@
 name: Build helpers
 on:
-  push
+  push:
+    paths:
+      - 'main/**'
+      - 'extra/**'
 jobs:
   build_docs:
     runs_on: ubuntu-latest