1827 multiple menu buttons

[LuLaValva]

• Fixes menu: menus for multiple form themed menu buttons aren't displayed properly #1827

• This PR contains CSS changes
• This PR does not contain CSS changes

Description

• Dropdown menu spanned whole set of buttons when multiple were placed next to each other.

Notes

• I modified dropdown-base instead of just menu-button for expandability, it did not break anything as far as my testing is concerned, so I think it is preferable.

Checklist

• I verify the build is in a non-broken state
• I verify all changes are within scope of the linked issue

• I regenerated all CSS files under dist folder
• I tested the UI in all supported browsers
• I tested the UI in dark mode and RTL mode
• I added/updated/removed Storybook coverage as appropriate

[agliga]

Looks good overall, but two comments on this that need to be fixed

• on ltr, we need to do left: unset and right: 0
• on --reverse we need to also unset the left and set right to 0. For ltr we should do the opposite.

This is whats happening on reverse menu button.

But setting right to 0 and left to unset works:

For LTR, it looks fine until you have a large item:

But setting right to 0 it works fine

I think with those changes we should be good.

[ArtBlue]

Approving with the condition that Andrew's recommended fix be applied for certain use cases.

[ArtBlue]

Hmm...is this arg doing anything? Doesn't look necessary.

[agliga]

Agreed, this argument isn't needed.
The rest of the PR looks good though.