nixos/jitsi-meet: fix prosody configuration (#434201)

nixos/modules/services/web-apps/jitsi-meet.nix

···
         "speakerstats"
         "external_services"
         "conference_duration"
-        "end_conference"
         "muc_lobby_rooms"
         "muc_breakout_rooms"
         "av_moderation"
···
           ''
             muc_mapper_domain_base = "${cfg.hostName}"
 
-            cross_domain_websocket = true;
+            http_cors_override = {
+              websocket = { enabled = true }
+            }
             consider_websocket_secure = true;
 
             unlimited_jids = {
···
           conference_duration_component = "conferenceduration.${cfg.hostName}"
           end_conference_component = "endconference.${cfg.hostName}"
 
-          c2s_require_encryption = false
           lobby_muc = "lobby.${cfg.hostName}"
           breakout_rooms_muc = "breakout.${cfg.hostName}"
           room_metadata_component = "metadata.${cfg.hostName}"