[ci][ez] Rename artifact from process_artifacts_combined

Build artifacts are uniquely associated to a single workflow run, so
appending the sha was unnecessary. I originally included it to make it
easier to download later but this turns out to be unneeded.

Drops the sha suffix to make downloading the artifact in a separate
script / workflow more straightforward.

ghstack-source-id: 36ac4df4c3
Pull Request resolved: https://github.com/facebook/react/pull/30364

.github/workflows/runtime_build_and_test.yml

@@ -285,7 +285,7 @@ jobs:
       - name: Archive build artifacts
         uses: actions/upload-artifact@v4
         with:
-          name: combined_artifacts_${{ github.sha }}
+          name: artifacts_combined
           path: |
             ./build.tgz
             ./build2.tgz