Bug 40788: Disable AS's calls to home.

We now also disable more AS tasks, but we could see it as a part of the
preferences we set to be sure it stays disabled.

The URL query stripping service is enabled only in nightly builds,
still it is initialized and remote settings are downloaded.
This adds a condition that prevents the service from being initialized
if disabled.

Upstream Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1812594
We should remove this patch if Mozilla decides that this is a problem
also for them, or if they do not but we decide to use the feature.