Deactivated tracks become activated again if profile sanitizing removes threads

I had a big Fission profile open where lots of processes were showing activity on the main thread. Every one of those processes was showing a Memory track and many were also showing a Network track. I then hid all those memory and network tracks because they were distracting.

Then I uploaded the profile, choosing not to include hidden threads.

After the upload, all the memory tracks appeared again.

This is the uploaded profile: https://share.firefox.dev/3gKo45S

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-288)