Restore ONVIF sensors

[hunterjm]

Proposed change

Add ability to restore sensors to ONVIF. On startup we pull data from the camera, but some states do not get returned until they change. This allows us to continue creating entities that were previously seen on the device and restore the last known state until it changes again.

This also fixes a bug introduced in #69708 where the sensor states were never updated.

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)
• 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 Add diagnostics to ONVIF #69708
• 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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[davet2001]

Minor comments (mostly questions that I couldn't be sure either way)

[hunterjm]

Minor comments (mostly questions that I couldn't be sure either way)

Hoepfully resolved/answered your comments/questions.

[davet2001]

From my point of view, this looks ok now, but probably would benefit from a 2nd review by someone else.

[balloob]

I removed the usage of hass.helpers because we're phasing it out (doesn't support typing) and replaced async_get_registry with async_get which is a callback.