Convert rc-nrr and slashcommands open to main module structure (#13520)

packages/rocketchat-nrr/client/index.js

@@ -0,0 +1 @@
+import './nrr';

packages/rocketchat-nrr/package.js

@@ -8,5 +8,5 @@ Package.describe({
 Package.onUse(function(api) {
 	api.use('ecmascript');
 
-	api.mainModule('nrr.js');
+	api.mainModule('client/index.js', 'client');
 });

packages/rocketchat-slashcommands-open/package.js

@@ -14,5 +14,5 @@ Package.onUse(function(api) {
 		'kadira:flow-router',
 		'templating',
 	]);
-	api.addFiles('client/index.js', 'client');
+	api.mainModule('client/index.js', 'client');
 });