Investigate and Fix leaks in API tests

[Cherrett]

Rationale

When running API tests on the UI Iteration 2 branch, we are getting the following warning:

In this ticket, we should investigate and fix these leaks. Please note that there are already a number of open handles which were sealed in the past. From the initial investigation, these new leaks seem to occur from the API V1 tests. Also, for some reason, this warning is not always shown.

For ticket closure

When running the API tests, this warning should no longer be displayed. This should be tested out on different machines since the occurrence of this warning is not always consistent.

[dillu24]

After I performed an investigation to try and detect where the issue is coming from I noticed that the issue might be coming from open connections from MongoDB, Mongoose and Redis. Since this requires us to change the structure of our code, I think that now is not the ideal time to do this.

Therefore, I suggest we remove this from the current sprint and from UI iteration 2 altogether. This is not a big deal as all tests are still passing, so this does not block us from releasing UI iteration 2.