### 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.
ERR_FAIL_INDEX_V(p_line, text.size(), 0);
	int col = 0;
	while (col < text[p_line].length() && is_whitespace(text[p_line][col])) {
		col++;
	}
	return col;
}
void TextEdit::swap_lines(int p_from_line, int p_to_line) {
	ERR_FAIL_INDEX(p_from_line, text.size());
	ERR_FAIL_INDEX(p_to_line, text.size());
	String tmp = get_line(p_from_line);
	String tmp2 = get_line(p_to_line);
	begin_complex_operation();
	set_line(p_to_line, tmp);
	set_line(p_from_line, tmp2);
	end_complex_operation();
}
void TextEdit::insert_line_at(int p_at, const String &p_text) {