Review Mozilla 1726524: Screen reader (narrate) in reader view doesn't work if privacy.resistFingerprinting is enabled

https://bugzilla.mozilla.org/show_bug.cgi?id=1726524

So Mozilla's solution here is to just disable text-to-speech in reader view entirely when privacy.resistFingerprinting is enabled, which kind of sucks. The argument is that the available voices is a big fingerprinting vector (which sure it is) but it seems either:

• reader view should be carved out somehow
• available voices could be normalized per platform

Set a due date to @ henry once he starts and has a gitlab account.

cc: @tom for your curiosity