Using the arrow keys in the search bar breaks the UI a bit

[dmint789]

Describe the bug
When searching for something in the search bar, if you press arrow up or arrow down, it automatically opens a match, and while the page is loading the UI is bugged and shows that match duplicated 3-4 times over.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://www.worldcubeassociation.org/
2. Click on the search box and start typing something that would give multiple results (e.g. "Euro")
3. Press arrow up or arrow down on the keyboard

Expected behavior
It should not automatically select a match until the user navigates to the desired match with the up/down arrows and presses Enter, and the matches should not be duplicated after selecting one.

[dunkOnIT]

Search bar is non-React, so it's fairly likely that we'll be replacing it entirely rather than fixing this bug - but will leave the issue open until it is replaced.