Add button text when no colors found

[KevinBatdorf]

Description

From #36543 I've added a CTA text for when the color palette has 0 colors.

From the linked issue:

• In the styles sidebar, in the color submenu, in the uncommon event there are no colour palettes (see image below), there should be an indicator or CTA so that users don’t need to manually navigate deep into the menus to add colours.

How has this been tested?

I tested this manually by adding/removing colors.

Screenshots

When colors is 0

When colors > 0

Types of changes

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).

--

N.B. It looks like Prettier is pushing the arguments passed in to sprintf two tabs deep instead of a single tab when paired with a ternary. I've seen this elsewhere in the codebase here so may require a patch to Prettier.

[github-actions]

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[ryanwelcher]

Thanks for the PR @KevinBatdorf! This looks good to me but you may want to double-check that the e2e failures are not related to this change.

[KevinBatdorf]

Thanks @ryanwelcher. Yeah, it seems like they just timed out. I wasn't sure about the etiquette in re-running the checks since they take awhile. I'll see if I can run them again now.

edit: I think someone with access will need to re-run them unless I make a trivial commit. I'll hold off on the latter.

[oandregal]

Thanks for this contribution, Kevin.

The e2e test failures look unrelated. I've restarted. If they fail again, would you mind rebasing this branch from trunk and pushing the changes again?

[github-actions]

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Kudos!