feat: opt into the masquerade bar slot

Declares the instructor-dashboard's route role under the
providesMasqueradeBarRolesId so the shell's masquerade bar renders on
this app's routes alongside the existing course navigation bar.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: arbrandes

src/provides.ts

@@ -1,8 +1,9 @@
-import { providesCourseNavigationRolesId } from '@openedx/frontend-base';
+import { providesCourseNavigationRolesId, providesMasqueradeBarRolesId } from '@openedx/frontend-base';
 import { instructorDashboardRole } from './constants';
 
 const provides = {
-  [providesCourseNavigationRolesId]: instructorDashboardRole
+  [providesCourseNavigationRolesId]: instructorDashboardRole,
+  [providesMasqueradeBarRolesId]: instructorDashboardRole,
 };
 
 export default provides;