Update custom component logic to always return a hint.

[Half-Shot]

Successor to #30320

This changes the modules custom components API to always the expected hints, filling in with defaults where a renderer does not provide expected values.

Needs playwright tests.

Checklist

• Tests written for new code (and old code if feasible).
• New or updated public/exported symbols have accurate TSDoc documentation.
• Linter and other CI checks pass.
• I have licensed the changes to Element by completing the Contributor License Agreement (CLA)

[t3chguy]

I'm not sure if this is better, as it happens after a Promise which may cause a visual flicker where one can be avoided

[Half-Shot]

I'm not sure if this is better, as it happens after a Promise which may cause a visual flicker where one can be avoided.

Yea, unsure. The intention is that by moving the defaults to the module layer, we don't need to replicate those defaults to every consumer of the hints. The alternative being I suppose that we change the type to be () => Promise<boolean>|boolean ..