Remove the retired local audio provider on installs that never played through it (#6029)

# What does this implement/fix?

The retired local audio provider showed its "requires attention" banner
on any machine that merely had a sound card, because the provider used
to enumerate every output device into a player config of its own. The
migration meant to spare those installs gated on the existence of a
`local_audio` player config, which is really the same question, so it
spared almost nobody.

Decide on evidence of playback instead: a `playlog` row keyed to the
player, or a persisted queue with a non-empty payload. With neither, the
provider config, its player configs, their DSP/queue settings, saved
queues and orphaned `spb_*` bridge configs are removed. The check needs
the databases, so it runs from `start()` before the providers load,
guarded by a one-shot flag; on any failure nothing is removed and the
notice shows.

**Related issue (if applicable):**

- #5965

## Types of changes

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- [ ] Bugfix (non-breaking change which fixes an issue) — `bugfix`
- [ ] New feature (non-breaking change which adds functionality) —
`new-feature`
- [x] Enhancement to an existing feature — `enhancement`
- [ ] New music/player/metadata/plugin provider — `new-provider`
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected) — `breaking-change`
- [ ] Refactor (no behaviour change) — `refactor`
- [ ] Documentation only — `documentation`
- [ ] Maintenance / chore — `maintenance`
- [ ] CI / workflow change — `ci`
- [ ] Dependencies bump — `dependencies`

## Checklist

- [x] The code change is tested and works locally.
- [x] `pre-commit run --all-files` passes.
- [x] `pytest` passes, and tests have been added/updated under `tests/`
where applicable.
- [x] For changes to shared models, the companion PR in
`music-assistant/models` is linked.
- [ ] For changes affecting the UI, the companion PR in
`music-assistant/frontend` is linked.
- [x] I have read and complied with the project's [AI
Policy](https://github.com/music-assistant/.github/blob/main/AI_POLICY.md)
for any AI-assisted contributions.
- [ ] I have [raised a PR against the documentation
repository](https://github.com/music-assistant/music-assistant.io/blob/main/CONTRIBUTING.md)
targeting the main or beta branch as appropriate.

---------

Co-authored-by: Marcel van der Veldt <[email protected]>
Co-authored-by: Copilot Autofix powered by AI <[email protected]>