prosody: fix XMPP_MUC_CONFIGURATION

prosody/rootfs/defaults/conf.d/jitsi-meet.cfg.lua

@@ -244,7 +244,7 @@ Component "{{ $XMPP_MUC_DOMAIN }}" "muc"
     muc_room_locking = false
     muc_room_default_public_jids = true
     {{ if .Env.XMPP_MUC_CONFIGURATION -}}
-    "{{ join "\"\n\"" (splitList "," .Env.XMPP_MUC_CONFIGURATION) }}";
+    {{ join "\n" (splitList "," .Env.XMPP_MUC_CONFIGURATION) }}
     {{ end -}}
 
 Component "focus.{{ $XMPP_DOMAIN }}" "client_proxy"