Windows: honor notification suppression when dismounting

Guard both direct SHChangeNotify flushes with DeviceChangeBroadcastDisabled.
These calls bypass BroadcastDeviceChange and its suppression check.

src/Common/Dlgcode.c

@@ -9827,7 +9827,7 @@ retry:
 	   removal before the process exits, leaving a ghost drive letter.
 	   Re-send the notification with SHCNF_FLUSH to force synchronous
 	   processing by Explorer before we return. */
-	if (Silent)
+	if (Silent && !DeviceChangeBroadcastDisabled)
 	{
 		wchar_t root[] = { (wchar_t) (nDosDriveNo + L'A'), L':', L'\\', 0 };
 		SHChangeNotify (SHCNE_DRIVEREMOVED, SHCNF_PATH | SHCNF_FLUSH, root, NULL);

src/Mount/Mount.c

@@ -6350,7 +6350,7 @@ retry:
 	/* GH #337, GH #1426: Flush shell notifications synchronously in
 	   silent/CLI mode to prevent ghost drive letters when the process
 	   exits immediately after dismount. */
-	if (Silent)
+	if (Silent && !DeviceChangeBroadcastDisabled)
 	{
 		DWORD removedDrives = prevMountList.ulMountedDrives & ~mountList.ulMountedDrives;
 		for (i = 0; i < 26; i++)