### 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.
Point2 mp = get_local_mouse_position();
	if (is_layout_rtl()) {
		mp.x = get_size().width - mp.x;
	}
	return mp;
}
String TextEdit::get_word_at_pos(const Vector2 &p_pos) const {
	Point2i pos = get_line_column_at_pos(p_pos);
	int row = pos.y;
	int col = pos.x;
	String s = text[row];
	if (s.length() == 0) {