Add unit translations for github integration

[abmantis]

Breaking change

The units of measurement of the following sensors for the github integration were changed to lowercase:

• Discussions
• Stars
• Watchers
• Forks
• Issues
• Pull requests

Proposed change

This adds native_unit_of_measurement translation to github integrations, as a basis implementation for home-assistant/architecture#1056

Needs home-assistant/frontend#22868

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: Add translations for measurement units architecture#1056 and Add support for unit_of_measurement translation frontend#22868
• Link to documentation pull request: Add section for unit of measurement translations developers.home-assistant#2451

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
• I have followed the perfect PR recommendations
• 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:

• 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.

[emontnemery]

We should extend the scope of this PR to not only add unit tests but also implementation changes

[gjohansson-ST]

Normally when implementing changes from arch discussions those PRs only introduce the changes/features needed in the entity components and not in integrations that might use it.

Are we doing something different here and there is no frontend PR (yet)?

[abmantis]

Normally when implementing changes from arch discussions those PRs only introduce the changes/features needed in the entity components and not in integrations that might use it.

There are no other changes on the entity components for this. I've kept only the changes on the youtube integration to make this simpler, though.

Are we doing something different here and there is no frontend PR (yet)?

Yes, there is work needed on the frontend too.

[abmantis]

Switched to the github integration since I can test it out with the frontend.

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

Learn more about our pull request process.

[frenck]

Thanks, @abmantis 👍

../Frenck