The profiler front-end gets confused about the profile start time in some profiles

It looks like the profiler gets confused about the start time of the profiler in profiles like this: https://share.firefox.dev/3IfJd6Z
(this is using the 'power' preset I'm thinking of adding in https://bugzilla.mozilla.org/show_bug.cgi?id=1778282)

My guess is that it gets confused by the use of the "Markers - All Threads" feature, but I'm not sure.
The part I really don't understand is how it decides how long the entire range is. Here are 3 profiles captured consecutively without touching the settings: https://share.firefox.dev/3Ik5RLj (range is wrong by about 8ms) https://share.firefox.dev/3yKwkP7 (range is wrong by 1.5s) https://share.firefox.dev/3RdVPzC (range is wrong by 420s)

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-557)