Deal with nested configs better in base class (#25237)
* Deal better with nested configs
* Fixes
* More fixes
* Fix last test
* Clean up existing configs
* Remove hack in MPT Config
* Update src/transformers/configuration_utils.py
Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>
* Fix setting a nested config via dict in the kwargs
* Adapt common test
* Add test for nested config load with dict
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Co-authored-by: Younes Belkada <49240599+younesbelkada@users.noreply.github.com>
