Make ``min-similarity-lines == 0`` stop similarity check (#4970)

* Make ``min-similarity-lines == 0`` stop similarity check
This makes it so that setting ``min-similarity-lines`` to zero exit the
similarity code checker with a successful exit.
This closes #4901

Co-authored-by: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
4 files changed