Fix front-end performance and scalability of search functionality in navigator

Given how many requests this currently generates to the server, I think it should be a beta blocker. Doubly so because it's a trivial fix on the client side.

This should be good for review now.

I can't sign off on this, this is a pure UI MR :)

There is a simpler approach to this using our already existing useDebounce hook. Hopefully the comments on the MR explain clearly how to implement it!