Win32: Remove changing the foreground lock timeout

It's rude to ignore the foreground lock timeout, especially by default.

Discussion of this code and its removal:
https://discourse.glfw.org/t/why-is-spi-setforegroundlocktimeout-set-to-zero-on-glfwinit-win32

src/win32_platform.h

@@ -330,7 +330,6 @@ typedef struct _GLFWlibraryWin32
 {
     HWND                helperWindowHandle;
     HDEVNOTIFY          deviceNotificationHandle;
-    DWORD               foregroundLockTimeout;
     int                 acquiredMonitorCount;
     char*               clipboardString;
     short int           keycodes[512];