Hi Vishal,
I think your requirement is to remove Mandatory Field error message if the event is not save, If this is your requirement, It can be done.
You need do code in DO_FINISH_INPUT
Add the following code there and I think it will work
DATA:
lv_event TYPE string.
SPLIT global_event AT '.' INTO lv_event lv_event.
TRANSLATE lv_event TO UPPER CASE.
IF lv_event NE 'SAVE' "Here Save is your Event name for save
global_messages>delete_message( condition = cl_bsp_wd_view_controller=>co_mandatory_field_empty ).
ENDIF.
I hope this was your requirement.
Thanks
Pratheek