fix(dropdowns): loosen up auto-placement settings

What does this MR do?

fix(dropdowns): loosen up auto-placement settings

Allows corner-positioned dropdowns to be auto-positioned in any corner if the prefered one lacks space for the dropdown to render properly. Previously, dropdowns could only be auto-positioned on the vertical axis, meaning that they would remain on the same side of their toggle. In rare cases, this poses issues for dropdowns that might also lack horizontal spacing and therefore need to be allowed to flip sides as well.

This is a reaction to a failure that currently blocks the @gitlab/ui upgrade MR at gitlab!124352 (merged). The failure is caused by !3530 (merged). The integration MR did not catch this: gitlab!124113 (closed).

How to reproduce the bug

1. Checkout the GitLab branch from gitlab!124352 (merged).
2. Run yarn.
3. In some epics board, click on the more icon next to an epic.
   • The dropdown is partially visible as it is left-aligned even though this causes it to overflow its container.
4. Checkout the branch from gitlab!124797 (closed).
5. Repeat steps 2-3.
   • The dropdown should now properly reposition itself to the left so that it's fully visible.

Screenshots or screen recordings

Before	After

Integration merge requests

• GitLab: gitlab!124797 (closed)
• [-] CustomersDot: mr_url
• [-] Status Page: mr_url

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