Resolve "Unhandled missing `allelereport` when inspecting work log"

Description

in getAlleleAssessmentMessage add a non null condition on allelereport.

Notes to review (code/docs/QA)

To reproduce in testdata:

• Start an analysis and finalize a variant
• Re-evalute the variant and set a new class, finalize
• Open Work log and choose All events

Related issues

Closes #2200 (closed)