Remove oauth2client dependency in Google Sheets

[tkdrob]

Breaking change

Proposed change

oauth2client was needlessly being used and not listed as a dependency. This will result in an error if the user goes to set up Google Sheets without setting up Google Calendar first.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

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  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
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[MartinHjelmare]

Thanks!

[epenet]

Would this leave the tests deterministic in the unlikely event that the URLs were accidently changed?

If oauth2client is available in the full test suite, maybe it's worth adding a test checking that the constants match?

from homeassistant.components.google_sheets import GOOGLE_AUTH_URI, GOOGLE_TOKEN_URI

def test_constants() -> None:
    """Ensure that local constants match auth2client constants."""
    try:
        import auth2client
    except ImportError:
        return
    assert GOOGLE_AUTH_URI == oauth2client.GOOGLE_AUTH_URI
    assert GOOGLE_TOKEN_URI == oauth2client.GOOGLE_TOKEN_URI

[MartinHjelmare]

I don't think we should do that. Each integration is responsible for connecting to the correct services and should require everything it needs to do that. It should not rely on resources outside its manifest that are not general resources.