search input/code insights: Page freezes due to CodeMirror based query input being re-rendered indefinitely

Created by: fkling

Steps to reproduce:

0. Enable CodeMirror query input by setting the experimental feature flag "editor": "codemirror6".
1. Go to new insights page https://sourcegraph.test:3443/insights/create/search?dashboardId=all
2. Enter something in the search query input (e.g. lang:test).

Expected behavior:

Page doesn't break.

Actual behavior:

Page freezes.

Preliminary investigation

Looks like the query input is re-rendered over and over again.