Remove AcceptsFocus() check from SetFocus()

This is partially a workaround for AcceptsFocus() not working as
expected for hidden windows under Mac (see the upcoming commits), but
also makes sense on its own: the other ports don't check whether the
window accepts focus in their SetFocus() implementation and it's not
clear why should Mac do this.

See #17340.

src/osx/window_osx.cpp

@@ -578,9 +578,6 @@ static bool wxIsWindowOrParentDisabled(wxWindow* w)
 
 void wxWindowMac::SetFocus()
 {
-    if ( !AcceptsFocus() )
-            return ;
-
     if (wxIsWindowOrParentDisabled((wxWindow*) this))
         return;