Recurse selection was not restricted to "mouse over icon" during range
selection (i.e. if we shift- double click on any area of tree element,
resurse select is still executed, which is wrong)
Also did a bit cleanup to use existing `is_over_icon` instead of calling
`outliner_item_is_co_over_icon` multiple times
Pull Request: https://projects.blender.org/blender/blender/pulls/118556
5f7b5a922d