fa6e104362
`WM_gizmomap_group_find` can return null when removing ruler annotation layer when current tool is not "Ruler" tool, this causes `ruler_item_remove` to crash. This fix made it only remove ruler items when `gzgroup` is not null (which is the same logic in `view3d_ruler_remove_invoke`). Pull Request: https://projects.blender.org/blender/blender/pulls/136416