Remove unused editor setting `editors/grid_map/palette_min_width`

This option is no longer used after the rework in #96922

Reported-by: Nodragem <[email protected]>

doc/classes/EditorSettings.xml

@@ -561,9 +561,6 @@
 		</member>
 		<member name="editors/bone_mapper/handle_colors/unset" type="Color" setter="" getter="">
 		</member>
-		<member name="editors/grid_map/palette_min_width" type="int" setter="" getter="">
-			Minimum width of GridMap's mesh palette side panel.
-		</member>
 		<member name="editors/grid_map/pick_distance" type="float" setter="" getter="">
 			The maximum distance at which tiles can be placed on a GridMap, relative to the camera position (in 3D units).
 		</member>

editor/settings/editor_settings.cpp

@@ -851,7 +851,6 @@ void EditorSettings::_load_defaults(Ref<ConfigFile> p_extra_config) {
 	// GridMap
 	// GridMapEditor
 	EDITOR_SETTING(Variant::FLOAT, PROPERTY_HINT_RANGE, "editors/grid_map/pick_distance", 5000.0, "1,8192,0.1,or_greater");
-	EDITOR_SETTING_USAGE(Variant::INT, PROPERTY_HINT_RANGE, "editors/grid_map/palette_min_width", 230, "100,500,1", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_RESTART_IF_CHANGED);
 	EDITOR_SETTING_BASIC(Variant::INT, PROPERTY_HINT_RANGE, "editors/grid_map/preview_size", 64, "16,128,1")
 
 	// 3D