Fix Wrong Shape Offsets in Tileset

Closes #30994

When modifying the properties of a tileset in the editor, some properties only apply to the first tile (such as the shape offset).

This change resolves that issue by traversing the changes to all of the shapes in the tileset instead of the first one.

scene/resources/tile_set.cpp

@@ -148,15 +148,20 @@ bool TileSet::_set(const StringName &p_name, const Variant &p_value) {
 			}
 		}
 	} else if (what == "shape")
-		tile_set_shape(id, 0, p_value);
+		for (int i = 0; i < tile_get_shape_count(id); i++)
+			tile_set_shape(id, i, p_value);
 	else if (what == "shape_offset")
-		tile_set_shape_offset(id, 0, p_value);
+		for (int i = 0; i < tile_get_shape_count(id); i++)
+			tile_set_shape_offset(id, i, p_value);
 	else if (what == "shape_transform")
-		tile_set_shape_transform(id, 0, p_value);
+		for (int i = 0; i < tile_get_shape_count(id); i++)
+			tile_set_shape_transform(id, i, p_value);
 	else if (what == "shape_one_way")
-		tile_set_shape_one_way(id, 0, p_value);
+		for (int i = 0; i < tile_get_shape_count(id); i++)
+			tile_set_shape_one_way(id, i, p_value);
 	else if (what == "shape_one_way_margin")
-		tile_set_shape_one_way_margin(id, 0, p_value);
+		for (int i = 0; i < tile_get_shape_count(id); i++)
+			tile_set_shape_one_way_margin(id, i, p_value);
 	else if (what == "shapes")
 		_tile_set_shapes(id, p_value);
 	else if (what == "occluder")