Dropdowns in edit board modal are misaligned

Steps to reproduce

• open any issue board (for example https://gitlab.com/groups/gitlab-org/-/boards/872907?milestone_title=11.9&&label_name[]=Plan)
• click Edit board
• open a dropdown (for example milestone)

What is the current bug behavior?

dropdowns are misaligned:

What is the expected correct behavior?

dropdowns are properly aligned:

Possible fixes

• short term:

- .boards-switcher .dropdown-menu.show
+ .boards-switcher > .dropdown-menu.show

in https://gitlab.com/gitlab-org/gitlab-ee/blob/master/ee/app/assets/stylesheets/pages/boards.scss

• long term:

The modal should be removed from the board switcher: