Fix material drag and drop

[jcostello]

My first PR 😄

Fixes: #74077

Explanation: When dragging over meshes with the same material (as the one dragged) and going over other mesh, material preview were reset but never assign again, causing to have a wrong state

[fire]

@SaracenOne you might be interested in looking at this one.

[SaracenOne]

Good catch! Though it doesn't quite fix it completely because the issue persists when using per-surface overrides (with the CTRL modifier).

My suggestion for fixing this fully is adding:
spatial_editor->set_preview_material_surface(-1); to line 4255

And removing it from line 4274

[jcostello]

Good catch! Though it doesn't quite fix it completely because the issue persists when using per-surface overrides (with the CTRL modifier).

Weird, I test it with CTRL and seems to be fixed. But I will re-test and try your solution

[jcostello]

@SaracenOne I applied that change. Seems to work fine

I also tried to remove the material override when ctrl is pressed. If there is a material override and you applied a surface override, you wont see anything because the material override is over everything. I couldn't make that change because when reseting the material, the surface information were lost because we only store the material of the last surface

[SaracenOne]

LGTM 👍

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉

[jcostello]

@akien-mga thanks <3