TST: Skip sumo uploader test if not installed

We cannot add fmu-sumo-uploader as a dependency, so skip the test if
`fmu.sumo` namespace cannot be found.

If some other `fmu.sumo` package ends up installed, this fixture may
need to be updated with the `.uploader` specificity, but importlib
find_spec will error out with that specificity at fmu.sumo before
reaching it.

tests/test_integration/test_wf_create_case_metadata.py

@@ -1,4 +1,5 @@
 import getpass
+import importlib
 import os
 import sys
 
@@ -75,7 +76,11 @@ def test_create_case_metadata_warns_without_overwriting(
 
 @pytest.mark.skipif(
     sys.version_info[:2] == (3, 12),
-    reason="fmu-sumo-uploader not compatible with Python 3.12",
+    reason="fmu-sumo-uploader not compatible with python 3.12",
+)
+@pytest.mark.skipif(
+    not importlib.util.find_spec("fmu.sumo"),
+    reason="fmu-sumo-uploader is not installed",
 )
 def test_create_case_metadata_enable_mocked_sumo(
     fmu_snakeoil_project, monkeypatch, mocker, mock_sumo_uploader