Some parts of the UI should be hidden for nostacksampling profiles

When seeing a profile with the nostacksampling feature, some parts of the UI that require samples look a bit broken.

Example profile: https://share.firefox.dev/3lsvZZ6

I think we should:

* Hide the "Call Tree", "Flame Graph" and "Stack Chart" panels by default. This would match the behavior we have with the "Network" panel that is only visible when the selected process has network markers. This would also result in the "Marker Chart" tab (which is the most useful for profiles with samples) being selected by default.
* Reduce the timeline track height: we don't need to keep the area where we usually show the activity graph, as we are sure it will always be empty.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-367)