fix: use Poetry with --no-root flag for GitHub Action dependencies

- Add Poetry installation to validate-datasets workflow
- Use --no-root to install dependencies without packaging the project
- Run validation script with 'poetry run' to access all dependencies
- Fixes ModuleNotFoundError for stopit and other dependencies when testing --describe functionality

Author: fcostaoliveira

.github/workflows/validate-datasets.yml

@@ -36,7 +36,7 @@ jobs:
 
     - name: Install dependencies
       run: |
-        poetry install
+        poetry install --no-root
         
     - name: Validate datasets.json
       run: |