DRY up attribute list handling with `attributeTokenList`

[myabc]

⚠️ This PR is based off #21134. Please review/merge that first.

Ticket

No ticket - just some small improvements that didn't really belong in #21134.

What are you trying to accomplish?

Uses recently introduced attributeTokenList to DRY up implementation of various Stimulus controllers/Angular components.

Merge checklist

• [ ] Added/updated tests
• [ ] Added/updated documentation in Lookbook (patterns, previews, etc)
• [ ] Tested major browsers (Chrome, Firefox, Edge, ...)

[myabc]

@akabiru was hoping you might be able to take a look at this since you know ckeditor-augmented-textarea better than me!