Remove duplicated CORS Origin

Signed-off-by: Tommy <contact@tommytran.io>

swag/nginx/proxy-confs/synapse.subdomain.conf

@@ -24,7 +24,6 @@ server {
       # Abuse reports should be sent to Mjölnir.
 
       # Add CORS, otherwise a browser will refuse this request.
-      add_header 'Access-Control-Allow-Origin' '*' always; # Note: '*' is for testing purposes. For your own server, you probably want to tighten this.
       add_header 'Access-Control-Allow-Credentials' 'true' always;
       add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
       add_header 'Access-Control-Allow-Headers' 'Authorization,Content-Type,Accept,Origin,User-Agent,DNT,Cache-Control,X-Mx-ReqToken,Keep-Alive,X-Requested-With,If-Modified-Since' always;