Respect documentation on passive log level
# What does this PR do?

The documentation states that setting a `log_level` to `"passive"` in the training arguments won't touch the log level, but this is not the case. Currently, setting `log_level` to `"passive"` is the same as setting it to `"info"`.
Likewise, setting `log_level_replica` to `"passive"` is the same as setting it to `"warning"`.

This PR fixes this and changes the default of `log_level_replica` to `"warning"` to have the same default for it. The question is whether we should change the default of `log_level` to `"info"` to have the same behavior as before, or leave it as is which would set it to warning unless the user has set their own Transformers verbosity to info like in the examples.

Related to #20154
_The documentation is not available anymore as the PR was closed or merged._<|||||>while at it could you please remind me what does `passive` actually imply?

> a 'passive' level which doesn't set anything and lets the application set the level

how does the application set the level? which application? perhaps we need a small example?<|||||>Hmm, this broke many deepspeed tests that were relying on info log level in deepspeed.

now deepspeed is no longer logging info `"DeepSpeed info: version={}, git-hash={}, git-branch={}"`

and thus the tests fail as it is looking for this string to tell DS is running.

Now, why would this change impact an underlying component I wonder.<|||||>OK, I now have to explicitly pass ` log_level="info" to trainer args to have the previous functionality. This looks like a BC breakage, no?

I adapted `get_regression_trainer` to have the original behavior here: https://github.com/huggingface/transformers/pull/21769 so it's all back to working.<|||||>Yes, I did mention it changed the behavior in the description of the PR and asked for how to proceed. You and Lysandre both agreed the break was worth it in this case.<|||||>Totally, Sylvain. I guess I struggle to understand when a BC breakage is ok and when it's not.