* Adding [T5/MT5/UMT5]ForTokenClassification
* Add auto mappings for T5ForTokenClassification and variants
* Adding ForTokenClassification to the list of models
* Adding attention_mask param to the T5ForTokenClassification test
* Remove outdated comment in test
* Adding EncoderOnly and Token Classification tests for MT5 and UMT5
* Fix typo in umt5 string
* Add tests for all the existing MT5 models
* Fix wrong comment in dependency_versions_table
* Reverting change to common test for _keys_to_ignore_on_load_missing
The test is correctly picking up redundant keys in _keys_to_ignore_on_load_missing.
* Removing _keys_to_ignore_on_missing from MT5 since the key is not used in the model
* Add fix-copies to MT5ModelTest
0d26abdd3a