DialogHeaderFooter should implement HasComponents

[Dudeplayz]

Describe your motivation

I think the Header and Footer of the Dialog should implement the HasComponents interface. It would simplify some things, also because I use Kotlin with extensions, which would then also be available for the footer and header.
Also methods like addComponentAtIndex/asFirst are missing at the moment.

Describe the solution you'd like

Dialog Header and Footer implements HasComponents

Describe alternatives you've considered

No response

Additional context

No response