Bugfix: Drop menus with limited vertical screen space

We've changed the way how drop menus are positioned when only limited vertical screen space is available. They now fully utilize the available vertical screen space.

https://github.com/owncloud/web/issues/8411
https://github.com/owncloud/web/issues/8412
https://github.com/owncloud/web/pull/8453
https://github.com/owncloud/web/pull/8584
