Replace use of `issues.issue_type` column with `issues.work_item_type_id` throughout code

Wherever we use issue_type, we need to start using the work_item_type. This will hit queries, permission checks, etc.

After we have removed all usage of the column and the issue_type_uses_work_item_types_table feature flag, we should remove the column from the DB as described in #402699 (closed)

Availability and Testing

Regression testing, please make sure e2e:package-and-test job is passing.

Ensure updated test coverage in unit/integration/feature tests.