[Unknown Mod][Combat] Grid display priority with large obstacles

[LeHerosInconnu]

In the original game as in fheroes2, the grid is displayed over the large obstacles contrary to the small obstacles.
This is changed and large obstacles are displayed over the grid as it is the case for the small obstacles.

In original game:

In‌ fheroes2:

Here is the test scenario file:
0 9947.zip

This is not an option.
This can be implemented directly in fheroes2.