[7.4-stable] Skip PushJavaScript Job for PRs without changed bun lock (#3222)

# Backport

This will backport the following commits from `main` to `7.4-stable`:
- [Merge pull request #3221 from
mamhoff/push-javascript-with-external-prs](#3221)

<!--- Backport version: 9.5.1 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sorenlouv/backport)

Co-authored-by: Martin Meyerhoff <[email protected]>

Author: alchemycms-ci-bot

.github/workflows/build_test.yml

@@ -174,15 +174,14 @@ jobs:
       contents: write
     runs-on: ubuntu-22.04
     needs: [check_bun_lock, RSpec]
-    if: github.event_name == 'pull_request'
+    if: github.event_name == 'pull_request' && needs.check_bun_lock.outputs.bun_lock_changed == 'true'
     steps:
       - uses: actions/checkout@v4
         with:
           ref: ${{ github.head_ref }}
           persist-credentials: false # otherwise, the token used is the GITHUB_TOKEN, instead of our personal access token.
           fetch-depth: 0 # otherwise, there would be errors pushing refs to the destination repository.
       - uses: actions/download-artifact@v4
-        if: needs.check_bun_lock.outputs.bun_lock_changed == 'true'
         with:
           name: javascript-bundles
           path: vendor/javascript