Use the marker schema to decide if we should show the markers in the timeline

Currently, we have a very naive check to decide whether to show the markers in the timeline or not:
https://github.com/firefox-devtools/profiler/blob/7e0be227b7a0aeb5935778af89e1c11be657ccdc/src/components/timeline/TrackThread.js#L219-L226
We are only looking at the thread name and decide if we should show the markers for that thread.
Instead of doing this check, we should look at the schemas of the markers inside the threads and decide if there is any marker to show for the timeline or not. This will allow us to remove this ad-hoc check, and will be more future-proof when people add interesting markers inside the other threads that they would like to see in the timeline.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-453)