Remove ObjectProcessor#getInputClass

Replace an explicit input class declaration with nasty reflection code.

server/src/main/java/envoy/server/processors/LoginCredentialProcessor.java

@@ -191,7 +191,4 @@ public final class LoginCredentialProcessor implements ObjectProcessor<LoginCred
 		// Complete the handshake
 		writeProxy.write(socketID, user.toCommon());
 	}
-
-	@Override
-	public Class<LoginCredentials> getInputClass() { return LoginCredentials.class; }
 }