Bug 1690412 Allow opening links from other apps in the running Firefox; r=mtabara,stransky

Without exporting org.mozilla.firefox.<profile_name> interface to the session bus
the Firefox cannot use the remote to open the links in the browser which
leads to running another instance showing the app is already running.

Differential Revision: https://phabricator.services.mozilla.com/D115817

taskcluster/docker/firefox-flatpak/runme.sh

@@ -157,6 +157,7 @@ flatpak build-finish build                                      \
         --talk-name="org.gtk.vfs.*"                             \
         --talk-name=org.freedesktop.Notifications               \
         --own-name="org.mpris.MediaPlayer2.firefox.*"           \
+        --own-name="org.mozilla.firefox.*"                      \
         --command=firefox
 
 flatpak build-export --disable-sandbox --no-update-summary --exclude='/share/runtime/langpack/*/*' repo build "$FLATPAK_BRANCH"