resteasy-multipart-provider erroneously depends on resteasy-client

resteasy-multipart-provider erroneously depends on resteasy-client and it shouldn't be the case. I noticed it while working on the Quarkus multipart extension.

After a discussion with Alessio, it looks like it was added here https://github.com/resteasy/Resteasy/commit/8c77c0e4996b2215f8ee3f588374bc480fbdc15b and that the scope should have been test.