Allow put custom label to ActionRadio.vue

[JuliaKirschenheuter]

resolves nextcloud/mail#1626

This is needed for extended labels as nextcloud/mail#1626 (comment)

[skjnldsv]

nextcloud/mail#1626 (comment)

[ChristophWurst]

I understand that this is a higher impact change but I don't see why it's bad per se.

Right now you can only use pure text for the label and no more specific markup.

The proposed alternative is to use a combination of action radio and action text. The difference I see is that with the alternative the actions are not grouped so that clicking the subline would also automatically select the radio. Only clicking the radio label selects the option.

I'm well aware that using a slot gives developers possible ways to create markup that isn't valid anymore.

Is there any other downside?

[skjnldsv]

A radio label can only contains text, anything else is not valid for html.
This has a much higher impact. We use the double-action in a various other places and it works fine.

This is not a bad idea per se, but needs a much broader discussion regarding how we view the Actions in general and how do we make sure the component stays compliant to html/accessibility standards as well as NC design standards :)