Enable jitsi-meet xmpp websockets

This switches desktop clients to using xmpp over websockets instead of
BOSH. The mobile clients continue to use BOSH. Apparently this provides
better performance and is the default expectation of the upstream docker
images. We had disabled it prior to get back to a working state when we
weren't setting this variable at all.

After looking at configs on the docker images I expect that enabling
this explicitly will work (the problem before was we neither enabled nor
disabled it and the images can't handle that case). If that isn't the
case we can always revert.

Change-Id: I59c9fe75a0860782beb8864ff3bd9622b35381c1

playbooks/roles/jitsi-meet/templates/meet-env.j2

@@ -138,8 +138,10 @@ ETHERPAD_URL_BASE=https://etherpad.opendev.org
 # Advanced configuration options (you generally don't need to change these)
 #
 
-# Needed to make newer jitsi meet happy. We may be able to switch this to 1
-ENABLE_XMPP_WEBSOCKET=0
+# This is used for signaling between desktop clients and the prosody server
+# instead of BOSH. The mobile clients continue to use BOSH. Supposedly this
+# should improve performance.
+ENABLE_XMPP_WEBSOCKET=1
 
 # Internal XMPP domain.
 XMPP_DOMAIN=localhost