修改用户权限保存接口，允许权限集合为空

src/main/java/com/qmth/ops/api/dto/UserPermissionDTO.java

@@ -16,7 +16,7 @@ public class UserPermissionDTO {
     private Long userId;
 
     @NotNull
-    @Size(min = 1)
+    @Size(min = 0)
     @Valid
     private List<PermissionDTO> permissions;