`ActionMenu` multiple variant does not support dynamic labels

[myabc]

ActionMenu multiple variant does not support dynamic labels.

To reproduce

Visit and compare:

• https://primer.style/view-components/lookbook/inspect/primer/alpha/action_menu/single_select_form
• https://primer.style/view-components/lookbook/inspect/primer/alpha/action_menu/multiple_select_form

Note

Primer's React implementation allows for this behavior by customizing the ActionMenu.Button:

      <ActionMenu.Button>
        <span className={classes.MutedText}>Options:</span> {selectedType.name}
      </ActionMenu.Button>

[myabc]

Hi @lesliecdubs, thanks for assigning me on this! This one is pretty self-explanatory so I didn't fill out the description - but I can do if that helps.

[lesliecdubs]

@myabc all good, I think the description is clear enough as is 🙂 Thanks for all your recent PRs! We'll work on getting reviews in over the next week or two.