[utils,smartcard] stop context thread on cancel all

When cancelling all smartcard context related operations also trigger
smartcard_call_context_signal_stop to terminate all related threads.

libfreerdp/utils/smartcard_call.c

@@ -2053,6 +2053,7 @@ BOOL smartcard_call_cancel_all_context(scard_call_context* ctx)
 {
 	WINPR_ASSERT(ctx);
 
+	smartcard_call_context_signal_stop(ctx, FALSE);
 	HashTable_Clear(ctx->rgSCardContextList);
 	return TRUE;
 }