chore: update Daily Test Coverage Improver to focus on React projects (#4759)

Author: yomybaby

.github/workflows/daily-test-improver.lock.yml

@@ -89,6 +89,7 @@ To decide which phase to perform:
 ## Phase 1 - Testing research
 
 1. Research the current state of test coverage in the repository. Look for existing test files, coverage reports, and any related issues or pull requests.
+  **Important:** Focus your research exclusively on the two projects located in `/react` directory and `/packages/backend.ai-ui` directory. Do not consider projects in other locations.
 
 2. Create a discussion with title "${{ github.workflow }} - Research and Plan" that includes:
   - A summary of your findings about the repository, its testing strategies, its test coverage