Delete wxListCtrl item data after handling its deletion event in wxMSW.

Delete wxListCtrl item data after handling its deletion event in wxMSW.

We deleted the data associated with the item too soon as we did it before the
handler for the item deletion event was run and this handler could still
access this data.

Only free the data after the handler returns now.

Closes #12449.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65536 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775