[회원가입][Bug] 호환성을 위한 코드 변경

- getActivity() -> getView()

app/src/main/java/kr/co/zumo/app/lifeplus/view/fragment/signup/SignUpFragment.java

@@ -56,7 +56,7 @@ public class SignUpFragment extends FragmentBase {
     SignUpViewModel signUpViewModel = new SignUpViewModel(new FragmentChanger(helper.getFragmentActivity(), helper.getContainerId(), new BasicFragmentFactory()));
     adapter = new SignUpAdapter(signUpViewModel);
 
-    RecyclerView recyclerView = getActivity().findViewById(R.id.sign_up_list);
+    RecyclerView recyclerView = getView().findViewById(R.id.sign_up_list);
     recyclerView.setHasFixedSize(true);
     RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(App.getInstance().getContext());
     recyclerView.setLayoutManager(layoutManager);