fix(settings): fix crash during settings update when not using oauth [EE-7031] (#11661)

api/http/handler/settings/settings_update.go

@@ -96,9 +96,11 @@ func (payload *settingsUpdatePayload) Validate(r *http.Request) error {
 		}
 	}
 
+	if payload.OAuthSettings != nil {
 		if payload.OAuthSettings.AuthStyle < oauth2.AuthStyleAutoDetect || payload.OAuthSettings.AuthStyle > oauth2.AuthStyleInHeader {
 			return errors.New("Invalid OAuth AuthStyle")
 		}
+	}
 	return nil
 }