Prevent enabling identity OAuth username/password on errors

app/src/main/java/eu/faircode/email/FragmentIdentity.java

@@ -638,6 +638,11 @@ public class FragmentIdentity extends FragmentBase {
                 saving = false;
                 getActivity().invalidateOptionsMenu();
                 Helper.setViewsEnabled(view, true);
+                if (auth != AUTH_TYPE_PASSWORD) {
+                    etUser.setEnabled(false);
+                    tilPassword.setEnabled(false);
+                    btnCertificate.setEnabled(false);
+                }
                 pbSave.setVisibility(View.GONE);
             }