Nimbus features can now specify a list of applications they support (defaulting
to firefox-desktop). Enrollment for a given recipe will only occur if the
application supports all the features listed in the experiment. This allows
Firefox Desktop and the background task service to have different sets of
features, which prevents Firefox from enrolling in backgroundTaskMessage
experiments and the background task service from enrolling in experiments
intended for Firefox Desktop.
Differential Revision: https://phabricator.services.mozilla.com/D153119
d8aa23c948