Workflows fixes and improvements (#1398)

.github/workflows/linux-ci.yml

@@ -163,21 +163,13 @@ jobs:
         id: render_test
         run: xvfb-run -a ./mbgl-render-test-runner --manifestPath=metrics/linux-gcc8-release-style.json
 
-      - name: Save PR number
-        if: always() && steps.render_test.outcome != 'failure'
-        env:
-          PR_NUMBER: ${{ github.event.number }}
-        run: |
-          echo $PR_NUMBER > ./pr_number
-
       - name: Upload render test result
-        if: always() && steps.render_test.outcome != 'failure'
+        if: always() && steps.render_test.outcome == 'failure'
         uses: actions/upload-artifact@v3
         with:
           name: render-test-result
           path: |
             metrics/linux-gcc8-release-style.html
-            ./pr_number
 
   coverage:
     runs-on: ubuntu-22.04