The UserService.setUser method should detect M2M tokens

[chrisala]

When running the functional tests, an issue arose whereby the user was being set to the jwtId (which is the stubbed M2M token user for MERIT->ecodata comms in the test).

This is because the getUserFromJWT is making a call to get the user profile for the presented JWT which presumably returns 404 in the real environment but because of the stubbing was returning a profile in the tests.

However, we don't want to be making this call and having it return 404 for every request from MERIT (or BioCollect) to ecodata.

We should probably either preference the userId header or detect the M2M token via other means and not make this call.