[scolv] make eventedit.scripts.column.* work

[luca-s]

Currently the special values added by eventedit.scripts.column.* are never visualized on the event edit tab of scolv

[luca-s]

Just to provide more context, the issue was in PublicObjectEvaluator, which was failing to load origins from the database because the required RTTI was missing from job.classType. Instead, a string was passed. This PR fixes that issue.

Interestingly, if the user had the same scripts configured in the event list tab, the special columns in the event edit tab would still be populated for the currently selected origin (and only that row). This happened because the EventEdit::evalResultAvailable callback was triggered by the PublicObjectEvaluator instance used by the event list tab. In that code path, the correct RTTI information was passed, so the evaluation completed successfully.