Fix PlayerListControl re-raising selection changed when repopulated. (#25412)

Fix PlayerListControl re-raising selection changed when repopulated. (#25412)

Now we just skip duplicate "item pressed" events from the ListContainer.

This caused the ahelp window to unfocus the message box after sending something. Flow is something like this: you send ahelp -> bwoink window refreshes player list due to new bwoink -> repopulated player list -> sent selection change -> repopulates right pane -> line edit gets unfocused.