Showing all tracks of a profile with several hundred tracks janks the UI for more than 20 seconds

Here is the profile I used as a test case:
1. Load https://share.firefox.dev/3QYQnCg
2. Click "Show all tracks"

Profile of doing this:
- on the currently deployed front-end: https://share.firefox.dev/47oTnOe
- on my local copy where the code is not minified: https://share.firefox.dev/3SR4ivN

In these profiles I notice that we have lots of `SetNeedStyleFlush` markers with `set CSS2Properties.width` as a label frame near the top of the stack. That may be an indication that we are doing too much with the DOM.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-15)