comet_ml logger update

[japdubengsub]

What does this PR do?

Hi, this is the PR from Comet's SDK engineer.
In this pull request, the CometML logger was updated to support the recent Comet SDK. Also:

• unified with the comet_ml.start() method to ensure ease of use
• removed deprecated REST API key
• enabled support for nested hyper parameters
• backward compatibility with previous versions has been maintained.

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📚 Documentation preview 📚: https://pytorch-lightning--20275.org.readthedocs.build/en/20275/

[RahulVadisetty91]

Before mocking, ensure these methods exist or update the test logic to mock accessible methods or properties. You might also want to log or assert that these attributes are successfully mocked to catch any potential issues during runtime.

[japdubengsub]

Hi everyone! In the latest commit, I fixed a couple of unit tests related to the changes in this branch. If there's anything else that needs to be adjusted, please let me know.

[Ritesh313]

Hi @japdubengsub I want to try out this new branch and having trouble getting it to work (getting errors at trainer.fit() step). Could you confirm if i'm installing the right branch:
pip install git+https://github.com/comet-ml/pytorch-lightning.git@feature/comet-logger-update

[japdubengsub]

Hi @Ritesh313!
Thank you for the feedback! Yes, the branch is correct. In recent commits, the fix for this error and support for the old experiment_name parameter were added.

[Borda]

why not os.environ.get() any more
these default seems strange, then rather None

[japdubengsub]

My intention here was to simplify the example of passing parameters, as if the parameters are already set as environment variables, they don't need to be specified—they'll be automatically picked up. However, if you believe it's clearer as it was before, I can revert the changes.

[Borda]

Suggested change

	api_key (str, optional): Comet API key. It's recommended to configure the API Key with `comet login`.
	api_key: Comet API key. It's recommended to configure the API Key with `comet login`.

please remove all typing here as it is already used from function footprint