tests: do not run node_exporter test on clients

We need to skip these tests on client nodes since we don't deploy
node_exporter on them anymore

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit 5650a6d7d0)

tests/conftest.py

@@ -141,6 +141,9 @@ def node(host, request):
         pytest.skip(
             "Not a valid test with dashboard disabled")
 
+    if request.node.get_closest_marker("dashboard") and group_names == ['clients']:
+        pytest.skip('Not a valid test for client node')
+
     data = dict(
         vars=ansible_vars,
         docker=docker,