Use same style for optional and avoid double check

I did not know that `std::optional::value()` did checked access. And I
still prefer a more explicit .has_value() over boolean conversion, but
this seems to be the accepted way to do this.

src/wine-host/utils.cpp

@@ -26,8 +26,8 @@ Win32Timer::Win32Timer(HWND window_handle,
 }
 
 Win32Timer::~Win32Timer() {
-    if (timer_id.has_value()) {
-        KillTimer(window_handle, timer_id.value());
+    if (timer_id) {
+        KillTimer(window_handle, *timer_id);
     }
 }