[BugFix] Fix root logger configuration being modified by PaddleOCR imports - #18247

Motivation

Importing paddleocr triggers dependency imports (e.g., paddlex, paddle) that may modify the root logger's level or handlers. This causes issues where users who configure logging *before* importing PaddleOCR find their log output silenced after the import.

Modifications

• paddleocr/__init__.py: Save the root logger's level and handler list before module imports, then restore them after all imports complete. This ensures PaddleOCR does not interfere with the calling application's logging configuration.
• tests/unit/test_logging_restore.py: Added unit tests validating the save/restore mechanism handles level changes, handler additions, handler removals, and the no-op case.

Usage or Command

N/A

Accuracy Tests

N/A - logging change only, no model accuracy impact.

Checklist

• Add at least a tag in the PR title.
• Format your code, run pre-commit before commit.
• Add unit tests.
• Provide accuracy results.
• If the current PR is submitting to the release branch, make sure the PR has been submitted to the main branch, then cherry-pick it to the release branch with the [Cherry-Pick] PR tag.

Closes #14955