Advise to run the profiler tool in a dedicated profile

This bug is opened as a follow-up of the Profiler server Rapid Risk Assessment (see [Risk Record bug](https://bugzilla.mozilla.org/show_bug.cgi?id=1594327)).

In the current state of things, data from all tabs are being captured in the profile.
This could result in uploading potentially and accidentally sensitive/private data online which could not be immediately deleted by users.
Advising people to use a dedicated profile before capturing data could be a mitigation measure against this particular scenario.

CC'ing julienw for follow-up on the RRA.

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-214)