fix: match DNS question with unescaped service name

[b-kamphorst]

Closes #50

@brutella the test that I added passes for v1.2.11 and fails for v1.2.12 and v1.2.13. I identified the issue to the question/response logic as expected. Either the question should have an escaped name, or the question handler should match to the unescaped service name. I thought that it should be the latter, but please review.

Note: the test that I added is a copy of the test TestRegisterServiceWithExplicitIP with changed service name. No further thought went into that, so feel free to simplify the test.