[Tests] Validate metadata for retrieved constants before validating the corrected files

Description

This MR addresses: https://git.xfel.eu/calibration/pycalibration/-/issues/89

In case the retrieved constants are different, the tests should realize this before validating the corrected files. This help in understanding the reason for the test failure instead of spending time investigating why the files were not validated and have different values.

How Has This Been Tested?

• Tested locally after changing parameters of one test to get the wrong Calibration constants.
• CI-InProgress

Relevant Documents (optional)

Types of changes

• Test (additional or refactored tests)

Checklist:

Reviewers

@kluyvert @schmidtp

tests/test_reference_runs/test_pre_deployment.py

@@ -371,9 +371,9 @@ def test_xfel_calibrate(
         metadata_file = f"calibration_metadata_{cal_conf['karabo-id']}.yml"
         # Load the relevant section from both files
         ccvs_test = load_yaml(
-            out_folder / metadata_file)["retrieved-constants"]
+            out_folder / metadata_file).get("retrieved-constants", {})
         ccvs_reference = load_yaml(
-            reference_folder / metadata_file)["retrieved-constants"]
+            reference_folder / metadata_file).get("retrieved-constants", {})
         ccvs_diff = DeepDiff(ccvs_test, ccvs_reference, ignore_order=True)
         assert ccvs_diff == {}, "Found difference in the metadata for the retrieved Constants."  # noqa
         LOGGER.info("Retrieved CCVs validated.")