Fix creation dialog for custom room types not appearing

... when opening the `/create-channel`-URL

packages/rocketchat-ui/client/views/app/createRooms.html

@@ -1,10 +1,11 @@
 <template name="createRooms">
-	<section class="create-channel">
-		{{#if tabsNeeded }}
-			{{> tabContainer tabs=tabs}}
-		{{else}}
-			{{> createChannel }}
-		{{/if}}
-	</section>
-
+	{{#if authorizationsLoaded }}
+		<section class="create-channel">
+			{{#if tabsNeeded }}
+				{{> tabContainer tabs=tabs}}
+			{{else}}
+				{{> createChannel }}
+			{{/if}}
+		</section>
+	{{/if}}
 </template>

packages/rocketchat-ui/client/views/app/createRooms.js

@@ -39,11 +39,22 @@ Template.createRooms.helpers({
 	tabsNeeded() {
 		const instance = Template.instance();
 		return !!(instance.data.roomTypesBeforeStandard.length || instance.data.roomTypesAfterStandard.length);
+	},
+
+	authorizationsLoaded() {
+		return RocketChat.authz.cachedCollection.ready.get();
 	}
 });
 
 Template.createRooms.onCreated(function() {
-	this.data.roomTypesBeforeStandard = roomTypesBeforeStandard();
-	this.data.roomTypesAfterStandard = roomTypesAfterStandard();
-	this.data.tabs = allTemplatesOrdered();
+	Tracker.autorun(()=> {
+		const authLoaded = RocketChat.authz.cachedCollection.ready.get();
+		if (authLoaded) {
+			// custom room types might verify authorization before they decide to be visible.
+			// This is only possible once the authorizations, which are a cached collection, are loaded
+			this.data.roomTypesBeforeStandard = roomTypesBeforeStandard();
+			this.data.roomTypesAfterStandard = roomTypesAfterStandard();
+		}
+		this.data.tabs = allTemplatesOrdered();
+	});
 });