Revert "Fix aside affecting parent popover height (#11859)" (#11942)

This reverts commit d3dfa91254f8cbc7f4779463b30a3df1677c395d.

This change can cause weird behavior where the completion menu ends up
positioned away from the cursor location:

<img width="1062" alt="Screenshot 2024-05-16 at 6 43 17 PM"
src="https://github.com/zed-industries/zed/assets/1486634/0462a874-4fe3-4ca9-88ce-8d5d0b4009fe">

With the change reverted:

<img width="1026" alt="Screenshot 2024-05-16 at 6 43 35 PM"
src="https://github.com/zed-industries/zed/assets/1486634/9fc7b9a1-0cfb-4a84-8f6b-b481a785ceca">

Release Notes:

- Fixed an issue where the completion menu would sometimes appear
detached from the cursor location (preview only).