Add a dashboard for broadcast services

This is just a placeholder for now

tests/app/main/views/test_broadcast.py

@@ -5,6 +5,7 @@ from tests.conftest import SERVICE_ONE_ID
 
 
 @pytest.mark.parametrize('endpoint, extra_args', (
+    ('.broadcast_dashboard', {}),
     ('.broadcast', {}),
     ('.preview_broadcast_areas', {}),
     ('.choose_broadcast_library', {}),
@@ -25,6 +26,17 @@ def test_broadcast_pages_403_without_permission(
     )
 
 
+def test_broadcast_dashboard(
+    client_request,
+    service_one,
+):
+    service_one['permissions'] += ['broadcast']
+    client_request.get(
+        '.broadcast_dashboard',
+        service_id=SERVICE_ONE_ID,
+    ),
+
+
 def test_broadcast_page(
     client_request,
     service_one,