ALTER TRIGGER validation should report 'trigger not found' instead of 'column does not belong'

[arvanus]

Description

When attempting to execute ALTER TRIGGER on a non-existent trigger, the error message reports a column validation error instead of a more appropriate 'trigger not found' message.

Steps to Reproduce

SET TERM ^ ;
ALTER TRIGGER DUMMY_NAME_NOT_FOUND_AIUD0 ACTIVE
AFTER INSERT OR UPDATE OR DELETE POSITION 0
AS
begin
   new.dummy = false;
end
^
SET TERM ; ^

Current Error

SQL Message : -206
Column does not belong to referenced table

Engine Code    : 335544351
Engine Message :
unsuccessful metadata update
ALTER TRIGGER DUMMY_NAME_NOT_FOUND_AIUD0 failed
Dynamic SQL Error
SQL error code = -206
Column unknown
NEW.DUMMY

Expected Error

trigger DUMMY_NAME_NOT_FOUND_AIUD0 not found

Notes

This is a cosmetic issue in validation order. The trigger existence should be validated before attempting to validate the columns referenced in the trigger body.