Fix an issue when Ubuntu sh command doesn't support arrays

To support directory array we try to run `bash` instead of `sh`
```
DIRS=(
  ./dir1
  ./dir2
)
```

Author: alexshikov

.github/workflows/pull-request-checks.yml

@@ -53,7 +53,7 @@ jobs:
       - name: Validate Fonts
         run: |
           pip install --upgrade fonttools
-          sh ./scripts/validate_fonts.sh
+          bash ./scripts/validate_fonts.sh
       - name: Unit tests
         run: ./gradlew testDebugUnitTest
       - uses: actions/upload-artifact@v4