### Godot version

v4.0.beta15.official [4fa6edc88]

### System information

Windows 10

### Issue description

I use a custom keyboard layout (I made it myself), and it has «dead keys» (just like International keyboard layouts have). For example, if I press `'`, nothing happens, but if I press `a` after that, I'll get `á`. If I press `'` and `Space`, I'll get just `'`. And with my layout:
If I press `Shift + .` and then `a`, I will get `ᵄ`.
If I press `Shift + .` and then `Space`, I will get `>`.
If I press `Shift + [` and then `5`, I will get `₅`.
If I press `Shift + [` and then `Space`, I will get `{`.
In beta 14 and before, everything worked fine, but in beta 15 when I press `Shift + .` and `Space`, just nothing happens, I don't get `>`. Same for `Shift + [` and `Space`, I don't get `>`. It seems the problem is with `Shift`, because I still can type `á` (`'` and `a`) or `'` (`'` and `Space`), but not `ä` (`Shift + '` and `a`) or `"` (`Shift + '` and `Space`). In the latter cases I get `á` and `'` as if `Shift` were never pressed.

### Steps to reproduce

Install/add US International keyboard layout or [Extended Latin keyboard layout](https://github.com/godotengine/godot/files/10494466/Layouts.zip) (just run `Extended Latin\ExtLat6\setup.exe`).
Open script editor.
Press `Shift + '`.
Then press `a`.

### Minimal reproduction project

N/A
KeyMappingWindows::initialize();
	drop_events = false;
	key_event_pos = 0;
	alt_mem = false;
	gr_mem = false;
	shift_mem = false;
	control_mem = false;
	meta_mem = false;
	hInstance = static_cast<OS_Windows *>(OS::get_singleton())->get_hinstance();
	pressrc = 0;
	old_invalid = true;
	mouse_mode = MOUSE_MODE_VISIBLE;
	rendering_driver = p_rendering_driver;
	
	tts = memnew(TTS_Windows);
	
	screen_set_keep_on(GLOBAL_GET("display/window/energy_saving/keep_screen_on"));
	
	OSVERSIONINFOW os_ver;
	ZeroMemory(&os_ver, sizeof(OSVERSIONINFOW));
	os_ver.dwOSVersionInfoSize = sizeof(OSVERSIONINFOW);
	HMODULE nt_lib = LoadLibraryW(L"ntdll.dll");
	if (nt_lib) {
		RtlGetVersionPtr RtlGetVersion = (RtlGetVersionPtr)GetProcAddress(nt_lib, "RtlGetVersion");
		if (RtlGetVersion) {