Update artifact upload condition and file extension in CI

Restrict video artifact uploads to Ubuntu runners on failure and change the file extension from `.mp4` to `.avi`. This ensures better alignment with the expected platform outputs and maintains consistency in artifact storage.

Author: VitaliyBoyko

.github/workflows/gradle.yml

@@ -59,12 +59,12 @@ jobs:
         run: ./gradlew test
 
       - name: Capture Test Artifacts on Failure
-        if: failure()
+        if: failure() && matrix.os == 'ubuntu-latest'
         run: |
           mkdir -p artifacts/videos
           latest_file=$(ls -Art video | tail -n 1)
           if [ -n "$latest_file" ]; then
-            cp "video/$latest_file" "artifacts/videos/latest-test-video.mp4"
+            cp "video/$latest_file" "artifacts/videos/latest-test-video.avi"
           fi
         shell: bash