transformers

33966811 - Add SequenceClassification and MultipleChoice TF models to Electra (#6227)

Add SequenceClassification and MultipleChoice TF models to Electra (#6227) * Add SequenceClassification and MultipleChoice TF models to Electra * Apply style * Add summary_proj_to_labels to Electra config * Finally mirroring the PT version of these models * Apply style * Fix Electra test