fix(schema): preserve Griffe logger inheritance

[sylvesterkaczmarek]

Summary

• restore the Griffe logger's configured level after docstring parsing
• preserve NOTSET inheritance instead of replacing it with the inherited effective level
• keep warning suppression during parsing unchanged

_suppress_griffe_logging() captured logger.getEffectiveLevel(). When the griffe logger inherited its level via NOTSET, leaving the context permanently replaced NOTSET with the inherited numeric level and changed future logging configuration.

Test plan

• added focused regression coverage in tests/test_function_schema_logger_restore.py
• GitHub Actions

Issue number

N/A