Bug 1696384 - Enable dom.event.wheel-deltaMode-lines.disabled in all channels. r=masayuki

It fixes a bunch of websites, and we don't have any known regression.

I think we could try to enable as-is but let me know if you'd prefer me
to look into fixing stuff like bug 1675949 (though I briefly looked into
it and it didn't seem quite trivial, though it should be doable from
DeltaAcummulator::InitLineOrPageDelta).

Your call though.

Differential Revision: https://phabricator.services.mozilla.com/D107195

modules/libpref/init/StaticPrefList.yaml

@@ -1769,7 +1769,7 @@
 # bug 1392460.
 - name: dom.event.wheel-deltaMode-lines.disabled
   type: bool
-  value: @IS_NIGHTLY_BUILD@
+  value: true
   mirror: always
 
 # Mostly for debugging. Whether we should do the same as