Work Package Templates - Delete Endpoint Unmocked Tests

Blocked By #2154

We are making tests in a new way that uses an actual database rather than mocking calls to prisma. You can run these tests by running yarn test:setup, then running yarn test (make sure to run yarn test:teardown whenever you're done). You can see examples of how to do these new tests in src\backend\tests\unmocked\team-type.test.ts; however, these tests are still pretty new, so it's likely you'll have to figure out something we haven't done yet.

This ticket is to make tests of this new type for the delete work package template endpoint (create a new file for this in the unmocked tests folder if need be)

Start with src\backend\tests\unmocked\team-type.test.ts to learn the database-backed test pattern, then locate the delete work package template endpoint. Run yarn test:setup before yarn test and yarn test:teardown afterward. Done means the endpoint has coverage in the unmocked tests folder without Prisma mocks.