fix: update workflow concurrency groups to enable run cancellation

- Refactor concurrency settings in `e2e-tests-split.yml` and `codecov-upload.yml` to remove SHA and run_id from group strings, allowing for proper cancellation of in-progress runs.
- Ensure that new pushes to the same branch cancel any ongoing workflow runs, improving CI efficiency and reducing queue times.

.github/workflows/codecov-upload.yml

@@ -19,7 +19,7 @@ on:
         type: boolean
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.ref_name }}-${{ github.run_id }}
+  group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
 env: