feat: make 'disabled' parameter of button component dynamic

[jfmcquade]

PR Checklist

• PR title descriptive (can be used in release notes)

Description

Enables the button component’s disabled/enabled state to dynamically reflect updates to the disabled parameter.

Additionally, this PR removes support within the button component for the row-level disabled property, which is considered deprecated. See follow-up #2761 to roll out this change to other components.

Dev notes

As we've discussed previously (for example, this comment thread on #2493), it would make sense to embrace angular signals more fundamentally in how we handle component parameters. This PR doesn't make any progress towards achieving this more generally, but ultimately it would likely make sense for all our authorable parameters to be parsed to computed/signal values that react to updates.

Git Issues

Closes #

Screenshots/Videos

Updated comp_button:

button.disabled.mov

[chrismclarke]

Always happy to move towards more signal calls, although could you just check the one inline comment to clarify some expected behaviour?

[jfmcquade]

@chrismclarke – Following our discussion, I've updated this PR to remove support within the button component for the row-level disabled property. I've added #2761 as a follow-up, to refactor other components to use a disabled component param as opposed to the row-level property.

@esmeetewinkel this PR is ready for functional testing.

[chrismclarke]

Apologies @jfmcquade - I actually made a refactoring PR targetting this but forgot to tag you for review
It's #2760 if you have a chance to look

[esmeetewinkel]

I'll test on refactor branch instead

[jfmcquade]

Merging as these changes have been tested on #2760