Add config_entries.async_wait_component

[emontnemery]

Proposed change

Add config_entries.async_wait_component()

config_entries.async_wait_component() waits for an entry's component to load and returns a bool indicating if the entry is loaded or not.
This is primarily intended for existing config entries which are loaded at startup, awaiting this function will block until the component and all its config entries are loaded.

Config entries which are created after Home Assistant is started can't be waited for, the function will just return if the config entry is loaded or not.

The use case is to make it possible for integration functionality to wait for its config entry to be loaded to avoid implementing integration specific synchronizations such as #76084

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.
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• Tests have been added to verify that the new code works.

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[emontnemery]

@thecode Some shelly and webostv negative tests now fail because integrations' async_validate_trigger_config is no longer called if the config entry is not set up. It's not really clear to me if the tests are no longer needed with the changes in this PR or if the tests need to be adjusted to setup the config entry.

[thecode]

Approved for Shelly & Webostv

[bdraco]

I didn't see this PR before, but just added something similar in #81771

It might make sense to refactor that now since it won't be a breaking change if we do it before 2022.12

[bdraco]

Thanks @emontnemery