test(fprintd): --finger doesn't work without dbus

`fprintd-enroll --finger` doesn't actually complete anything if dbus isn't
running. Check if dbus is running using 'busctl list'.

Author: yedayak

test/t/test_fprintd_enroll.py

@@ -13,6 +13,10 @@ def test_basic(self, completion):
     def test_options(self, completion):
         assert completion
 
-    @pytest.mark.complete("fprintd-enroll --finger ", require_cmd=True)
+    @pytest.mark.complete(
+        "fprintd-enroll --finger ",
+        require_cmd=True,
+        skipif="busctl list 2>/dev/null; (( $? == 1 ))",  # fprintd relies on dbus running
+    )
     def test_finger(self, completion):
         assert completion