Let users without send_messages view broadcasts

At the moment viewing a broadcast is limited to those users who have
the `send_messages` permission.

This doesn’t match how we describe the permissions on the team members
page

This commit makes it so that any team member can see a broadcast that’s
in any state other than `draft`.

tests/app/main/views/test_broadcast.py

@@ -639,6 +639,50 @@ def test_cant_approve_own_broadcast(
     )
 
 
+@freeze_time('2020-02-22T22:22:22.000000')
+def test_view_only_user_cant_approve_broadcast(
+    mocker,
+    client_request,
+    service_one,
+    active_user_with_permissions,
+    active_user_view_permissions,
+    mock_get_broadcast_template,
+    fake_uuid,
+):
+    mocker.patch(
+        'app.broadcast_message_api_client.get_broadcast_message',
+        return_value=broadcast_message_json(
+            id_=fake_uuid,
+            service_id=SERVICE_ONE_ID,
+            template_id=fake_uuid,
+            created_by_id=fake_uuid,
+            finishes_at='2020-02-23T23:23:23.000000',
+            status='pending-approval',
+        ),
+    )
+    mocker.patch('app.user_api_client.get_user', side_effect=[
+        active_user_view_permissions,  # Current user
+        active_user_with_permissions,  # User who created broadcast
+    ])
+    service_one['permissions'] += ['broadcast']
+
+    page = client_request.get(
+        '.view_broadcast_message',
+        service_id=SERVICE_ONE_ID,
+        broadcast_message_id=fake_uuid,
+    )
+
+    assert (
+        normalize_spaces(page.select_one('.banner').text)
+    ) == (
+        'This broadcast is waiting for approval '
+        'You don’t have permission to approve broadcasts.'
+    )
+
+    assert not page.select_one('form')
+    assert not page.select_one('.banner a')
+
+
 @pytest.mark.parametrize('initial_status, expected_approval', (
     ('draft', False,),
     ('pending-approval', True),