Add last automatic backup state sensor

[mib1185]

Proposed change

This adds the last_automatic_backup_state sensor

• the state of the last automatic backup, matches the state in the frontend of the Settings > System > Backup page
• is a string-enum entity, so is well suited to be automated on, as it has defined possible states
• is based on the backup internal KnownBackups data to avoid further calls to the backup agents

reference: feature request

Type of change

• [ ] Dependency upgrade
• [ ] Bugfix (non-breaking change which fixes an issue)
• [ ] New integration (thank you!)
• [x] 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: https://github.com/home-assistant/home-assistant.io/pull/38871
• Link to developer documentation pull request:
• Link to frontend pull request:

Checklist

• [x] The code change is tested and works locally.
• [x] Local tests pass. Your PR cannot be merged unless tests pass
• [x] There is no commented out code in this PR.
• [x] I have followed the development checklist
• [x] I have followed the perfect PR recommendations
• [x] The code has been formatted using Ruff (ruff format homeassistant tests)
• [ ] Tests have been added to verify that the new code works.

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

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

If the code communicates with devices, web services, or third-party tools:

• [ ] The manifest file has all fields filled out correctly.
  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.
• [ ] For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.

To help with the load of incoming pull requests:

• [ ] I have reviewed two other open pull requests in this repository.

[home-assistant[bot]]

Hey there @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (backup) you are listed as a code owner for? Thanks!

Code owner commands

Code owners of backup can trigger bot actions by commenting:

• @home-assistant close Closes the pull request.
• @home-assistant rename Awesome new title Renames the pull request.
• @home-assistant reopen Reopen the pull request.
• @home-assistant unassign backup Removes the current integration label and assignees on the pull request, add the integration domain after the command.
• @home-assistant add-label needs-more-information Add a label (needs-more-information, problem in dependency, problem in custom component) to the pull request.
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[MartinHjelmare]

I suggest you split the PR in two, one for each new sensor.

[mib1185]

I suggest you split the PR in two, one for each new sensor.

the last attempted sensor is now split into #144194 - ~will remove it from the current PR with a merge commit after the other PR got merged~ removed it now, to avoid dependencies between these PRs

[mib1185]

• superseded by #145350