[dagit] Fix JobMetadataQuery for non-crag

Summary: For non-crag users, don't include mode in the JobMetadataQuery params, since mode requires that they have migrated.

Test Plan: Load a job inside and outside of crag, verify that the query is performed with the desired params based on the flag.

Reviewers: bengotow, sandyryza, dgibson, alangenfeld

Reviewed By: alangenfeld

Differential Revision: https://dagster.phacility.com/D8991