[BUG] De-synchronization in PriorityGenomicContext when the GRR instance is overriden

[iordanivanov]

The issue encountered was with CLIAnnotationContext and GPFInstanceGenomicContext. A unit test for annotate_columns was using the --grr argument to provide a GRR instance for the tool from a fixture. This GRR instance did not contain a reference genome, so the PriorityGenomicContext would return a reference genome from the GPFInstanceGenomicContext. This reference genome did not exist in the fixture GRR, so the tool would crash when it attempted to get it by its id from the fixture GRR.