### 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.
if (alt_start && k->get_keycode() == Key::ALT) {
				alt_start = false;
				if ((alt_code > 0x31 && alt_code < 0xd800) || (alt_code > 0xdfff && alt_code <= 0x10ffff)) {
					char32_t ucodestr[2] = { (char32_t)alt_code, 0 };
					insert_text_at_caret(ucodestr);
				}
				accept_event();
				return;
			}
			return;
		}
		
		if (k->is_alt_pressed()) {
			if (!alt_start) {
				if (k->get_keycode() == Key::KP_ADD) {
					alt_start = true;
					alt_code = 0;
					accept_event();
					return;
				}
			} else {
				if (k->get_keycode() >= Key::KEY_0 && k->get_keycode() <= Key::KEY_9) {
					alt_code = alt_code << 4;
					alt_code += (uint32_t)(k->get_keycode() - Key::KEY_0);
				}
				if (k->get_keycode() >= Key::KP_0 && k->get_keycode() <= Key::KP_9) {
					alt_code = alt_code << 4;
					alt_code += (uint32_t)(k->get_keycode() - Key::KP_0);
				}
				if (k->get_keycode() >= Key::A && k->get_keycode() <= Key::F) {