Relax Unity menu interdiction hack to allow popup menus in modal dialogs.

The changes of r73007 fixed the problem with menus remaining active while a
modal dialog was shown (see #14823) but also disabled processing of the events
from any popup menus shown by the dialog itself. Reallow the latter while
still forbidding the former now by checking whether the window associated with
the menu is the dialog itself.

Closes #14961.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73365 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Allow hiding/showing already hidden/shown wxGrid rows/columns.

Don't assert if an already hidden/shown row/column is being hidden/shown again
but simply don't do anything. This is more convenient because the code outside
wxGrid has no efficient way to only hide a row/column if it's currently shown.

Closes #14960.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73366 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775