Scrollbar flicker when menu is near bottom

[tlmii]

Originally referenced in #2835 (comment)

There's a flicker of vertical scrollbar as the menu repositions itself, similar to what I saw when implementing #2572. The fix isn't quite as simple though, since we do want it to be able to overflow the bottom of the grid (unlike the right edge of the grid):

My original investigation made it seem like it was either an issue in the underlying web components or a conflict between the blazor components and the web components. The workaround for the original issue (menu on the right edge) was easy enough so I didn't investigate further. Now it seems like we need to go ahead and solve this.

@vnbaaij FYI, I know we discussed this a bit a few weeks ago. It appears that it renders briefly in place before quickly being repositioned based on the thresholds.

[leslierichardson95]

@adamint to investigate if this issue still exists.

[maddymontaquila]

I've confirmed this no longer repros!