Ray Tune Integration Updates
# What does this PR do?
- Automatically disables memory tracker if enabled since the memory tracker is not serializable
- Fixes the Ray Tune integration test
- Adds a new test for Ray Client API
- Adds integration tests back to the scheduled Github Actions pipeline

Closes #11249, https://github.com/huggingface/transformers/issues/12177 

@LysandreJik @richardliaw 

thanks @sgugger for the fast review! anything blocking to get this merged :) ?<|||||>This is good for me. You had standing questions for Lysandre so not sure it was ready to be merged, but I will do so if you tell me everything is okay on your side :-)<|||||>@sgugger yep this is ready to merge!<|||||>Thanks again!