Prevent scrolling of elements underneath search modal

Summary

Mousewheeling/scrolling on the search modal causes the underlying page/element to scroll when the the search modal does not scroll.

Steps to reproduce

1. Open the search modal
2. Try to scroll it past its scrollable bounds (just keep scrolling down, for instance)
3. Notice that the page underneath scrolls

Example Project

n/a

What is the current bug behavior?

The page/element underneath the modal scrolls.

What is the expected correct behavior?

The page/element underneath the modal should not scroll.

Relevant logs and/or screenshots

simplescreenrecorder-2023-07-28_12.42.20

Output of checks

This bug happens on GitLab.com

Proposed solution

As per this comment We can fix this by removing overflow-y: scroll from the html element. We just need to be sure there are no unintended consequences of this.