muc-views: admins can also change the MUC subject

spec/muc.js

@@ -3009,13 +3009,13 @@
                 textarea.value = '/help';
                 view.onKeyDown(enter);
                 info_messages = sizzle('.chat-info:not(.chat-event)', view.el);
-                expect(info_messages.length).toBe(17);
+                expect(info_messages.length).toBe(19);
                 let commands = info_messages.map(m => m.textContent.replace(/:.*$/, ''));
                 expect(commands).toEqual([
                     "You can run the following commands",
                     "/admin", "/ban", "/clear", "/deop", "/destroy",
                     "/help", "/kick", "/me", "/member", "/modtools", "/mute", "/nick",
-                    "/op", "/register", "/revoke", "/voice"
+                    "/op", "/register", "/revoke", "/subject", "/topic", "/voice"
                 ]);
                 occupant.set('affiliation', 'member');
                 textarea.value = '/clear';

src/converse-muc-views.js

@@ -1374,7 +1374,7 @@ converse.plugins.add('converse-muc-views', {
 
             getAllowedCommands () {
                 let allowed_commands = ['clear', 'help', 'me', 'nick', 'register'];
-                if (this.model.config.get('changesubject') || this.model.getOwnAffiliation() === 'owner') {
+                if (this.model.config.get('changesubject') || ['owner', 'admin'].includes(this.model.getOwnAffiliation())) {
                     allowed_commands = [...allowed_commands, ...['subject', 'topic']];
                 }
                 const occupant = this.model.occupants.findWhere({'jid': _converse.bare_jid});