test: pass tag concurrency correctly in integration tests

Context

I discovered that for the API integration tests, the importer tag concurrency was always set 1 one, regardless of the functional option being used. There are two problems resulting from this:

• We can't test tag import concurrency different than 1
• Using import concurrency = 0 to test blocking imports wasn't working, although the timing for the test which needed this has happened to work out, since Imports are a rather heavy operation.

Additionally, pre imports cannot be blocked using the import concurrency = 0 to concurrency method, as that only affects imports, so an additional test method was created to delay the end of both imports and pre imports.