fix: Don't remove the TURN port if it's the default. (#719)

3478 is default for TURN, but not for TURNS. Reported by @damencho.

modules/xmpp/strophe.jingle.js

                         dict.url += el.attr('host');
                         const port = el.attr('port');
 
-                        if (port && port !== '3478') {
+                        if (port) {
                             dict.url += `:${el.attr('port')}`;
                         }
                         const transport = el.attr('transport');