Tests - Fix how matching service client is accessed in functional tests

[gow]

What changed?

Functional tests now use the prepared Matching service client in the FunctionalTestBase object rather than reaching directly into FunctionalTestBase.testCluster.xyz.

Why?

Functional tests should not reach deep into the test suite object to get handles to dependencies. Without this change, some of the tests assume that we have an inline testCluster setup. This will not be true if we want to run the functional tests against an already running service.

How did you test it?

Existing tests.

Potential risks

N/A

Documentation

N/A

Is hotfix candidate?

No