### Godot version

4.0 beta 15

### System information

Windows 10

### Issue description

It happened with both Google IME and MS-IME, and there was no problem until Beta14.
When typing Japanese characters, it is common to select a character from the suggestion window and then start typing the next character before confirming.
In this case, uncommitted characters are forcibly committed, and input of the next character begins.

**↓Beta15**

https://user-images.githubusercontent.com/186786/214753450-b493cca6-2644-4b3d-8cd2-660565cc3547.mp4

**↓Beta14**

https://user-images.githubusercontent.com/186786/214755127-dde819cc-4d63-403a-99b0-09821671f74e.mp4



### Steps to reproduce

It happened with both Google IME and MS-IME in beta15

### Minimal reproduction project

It is project independent and happens in the editor.
for (int i = 0; i < key_event_pos; i++) {
		KeyEvent &ke = key_event_buffer[i];
		switch (ke.uMsg) {
			case WM_CHAR: {
				
				if (!KeyMappingWindows::is_extended_key(ke.wParam) && ((i == 0 && ke.uMsg == WM_CHAR) || (i > 0 && key_event_buffer[i - 1].uMsg == WM_CHAR))) {
					static char32_t prev_wc = 0;
					char32_t unicode = ke.wParam;
					if ((unicode & 0xfffffc00) == 0xd800) {
						if (prev_wc != 0) {
							ERR_PRINT("invalid utf16 surrogate input");
						}
						prev_wc = unicode;
						break; 
					} else if ((unicode & 0xfffffc00) == 0xdc00) {
						if (prev_wc == 0) {
							ERR_PRINT("invalid utf16 surrogate input");
							break; 
						}
						unicode = (prev_wc << 10UL) + unicode - ((0xd800 << 10UL) + 0xdc00 - 0x10000);
						prev_wc = 0;
					} else {
						prev_wc = 0;
					}