add apk to artifacts

Author: rozPierog

.github/workflows/performanceTests.yml

@@ -58,4 +58,8 @@ jobs:
     - uses: actions/upload-artifact@v4
       with:
         name: results-${{ github.head_ref || github.ref_name }}-${{ matrix.api-level }}-${{ matrix.target }}
-        path: results.json
+        path: results.json
+    - uses: actions/upload-artifact@v4
+      with:
+        name: test-app-${{ github.head_ref || github.ref_name }}-${{ matrix.api-level }}-${{ matrix.target }}
+        path: android/app/build/outputs/apk/release/app-release.apk