This fix T59358: Wrong status bar keymap for release confirms and right click select

When an operator is activated by one of the key items used by the modal
keymap, that modal keyitem cannot be activated (since the button is in use).

So it doesn't seem right to display these keyitens in the statusbar.

This patch proposes to skip a keyitem used for modalmap but which is
currently being used.

Ref T59358