feat: systemPreferences.getColor should return RGBA instead of RGB

[ILikeTeaALot]

Description of Change

Fully completes #26628

This fix implements the change requested in #26628, as stated there due to low usage of the API and the fact that returning a hex colour with alpha appended to the end should not cause any breaking changes, this is not marked as breaking.

(I don't have a recent-enough Mac to compile the code, so I would be immensely greatful for someone to take the time to do the necessary tests.)

The same change has not been made to the Windows version as no Windows system colour use alpha, however it could easily be changed as well for consistency.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• relevant documentation, tutorials, templates and examples are changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

No test changes are necessary, but as noted above I've been unable to run them myself.

Release Notes

Notes: Changed systemPreferences.getColor(name) to return an RGBA hex value (#RRGGBBAA) instead of a plain RGB (#RRGGBB) value.

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[zcbenz]

It was not settled that this kind of change should be a fix in #26628. The PR #30055 that changed getSystemColor to return RGBA was a fix because the document stated the API returned RGBA but the code did not.

Having said that I do think it is fine to mark this change as fix though, but it should be @electron/wg-api to decide.

Also the return value should also be changed on Windows/Linux too, even if those platforms do not use transparent colors we should still fill the value with a FF alpha value.

[erickzhao]

API LGTM

I agree with @zcbenz that the alpha channel FF should be added for consistency.

[itsananderson]

API LGTM

+1 for including FF on Win/Linux for consistency

[jkleinsc]

@ILikeTeaALot can you address @zcbenz's concerns?

[ILikeTeaALot]

@jkleinsc Happy to! Apologies I didn't see the activity on this PR.

The Windows version should work exactly the same now.

[codebytere]

API LGTM

[jkleinsc]

API LGTM

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Congrats on merging your first pull request! 🎉🎉🎉

[release-clerk]

Release Notes Persisted

Changed systemPreferences.getColor(name) to return an RGBA hex value (#RRGGBBAA) instead of a plain RGB (#RRGGBB) value.