Clearable time selector

[schelv]

Proposed change

The time selector can now be cleared:

The same selector after pressing the clear button:

Type of change

• [ ] Dependency upgrade
• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (thank you!)
• [ ] Breaking change (fix/feature causing existing functionality to break)
• [ ] Code quality improvements to existing code or addition of tests

Example configuration

Additional information

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

Checklist

• [x] The code change is tested and works locally.
• [x] There is no commented out code in this PR.
• [ ] 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

[karwosts]

Once we get this would be good to add for duration selector as well, can fix #19360

[bdraco]

I think this will solve the issue where its not possible to clear a timeout without dropping back to YAML once its been set which seems like the root cause of https://github.com/home-assistant/core/issues/109586

It also resolves quandary in https://github.com/home-assistant/core/pull/115830 as it means it means we align the frontend to the backend

• no timeout set (cleared), no timeout happens
• 0 timeout set, times out right away

[schelv]

@bramkragten I see you added the "Needs UX" label. Does that mean that some action needs to be taken for this merge request?