`Artifact` class `scan` method generates type error attempting to retrieve scan_overview

[brophyja]

When Harbor is configured to run Trivy scans, the Artifact class's scan method generates type errors when attempting to retrieve the scan_overview (e.g. NativeReportSummary).

 /dev/run/ea-harbor/lib64/python3.12/site-packages/harborapi/models/models.py:2813 in scan

   2810     scan overview. This property provides a quick access to it.
   2811     """
   2812     if self.scan_overview and self.scan_overview.root:
 x 2813         return self.scan_overview.root[next(iter(self.scan_overview))]
   2814     return None
   2815     
   2816     


TypeError: unhashable type: 'dict'

Perhaps the retrieval should return the dict values, for example:

2812         if self.scan_overview and self.scan_overview.root:
2813             return self.scan_overview.root[next(iter(self.scan_overview.values()))]
2814         return None

[brophyja]

Actually, I think this might be correct:

2812         if self.scan_overview and self.scan_overview.root:
2813             return(next(iter(self.scan_overview.root.values())))
2814         return None

The above change (line 2813) provides the correct scan severity when called by the 'harbor_cli' harbor.artifacts package's get_artifact_severity function.

     74 def get_artifact_severity(artifact: Artifact) -> str | None:
     75     """Attempt to get the severity string for an artifact.
     76     Not every artifact has a scan overview, and not every scan overview
     77     has a severity string.
     78     """
     79     try:
     80         return artifact.scan.severity  # type: ignore[attr-defined]
     81     except AttributeError:
     82         return None