simplify code of airflow job detection (#2978)

## Changes
Simplify code

### Linked issues
None

### Functionality
None

### Tests
- [x] ran unit tests

---------

Co-authored-by: Eric Vergnaud <[email protected]>

Author: ericvergnaud

src/databricks/labs/ucx/assessment/jobs.py

@@ -93,11 +93,11 @@ def _assess_jobs(self, all_jobs: list[BaseJob], all_clusters_by_id) -> Iterable[
             cluster_failures.extend(self._check_jar_task(job.settings.tasks))
             job_assessment[job_id].update(cluster_failures)
 
-        # TODO: next person looking at this - rewrite, as this code makes no sense
-        for job_key in job_details.keys():  # pylint: disable=consider-using-dict-items,consider-iterating-dictionary
-            job_details[job_key].failures = json.dumps(list(job_assessment[job_key]))
-            if len(job_assessment[job_key]) > 0:
-                job_details[job_key].success = 0
+        for job_key, job_info in job_details.items():
+            failures = job_assessment[job_key]
+            job_info.failures = json.dumps(list(failures))
+            if len(failures) > 0:
+                job_info.success = 0
         return list(job_details.values())
 
     @staticmethod