Fix warning "LLModalDialog::stopModal: LLModalDialog::stopModal not in list!" by properly pushing modal alert toasts on the modal dialog stack

Need to call onOpen() for modal alert toasts in setVisible() because the
virtual methods LLModalDialog::openFloater and LLModalDialog::onOpen() never
get invoked by LLFloater - this is only done by LLFloaterReg or if manually
doing so, but not for LLToast

indra/newview/lltoast.cpp

@@ -393,6 +393,12 @@ void LLToast::setVisible(BOOL show)
 		if (!getVisible())
 		{
 			LLModalDialog::setFrontmost(FALSE);
+			// <FS:Ansariel> Properly push the modal toast on the modal dialog stack
+			if (isModal())
+			{
+				onOpen(LLSD());
+			}
+			// </FS:Ansariel>
 		}
 	}
 	else