### 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 (placeholder_text == p_text) {
		return;
	}
	placeholder_text = p_text;
	_update_placeholder();
	queue_redraw();
}
String TextEdit::get_placeholder() const {
	return placeholder_text;
}
void TextEdit::set_line(int p_line, const String &p_new_text) {
	if (p_line < 0 || p_line >= text.size()) {
		return;
	}
	begin_complex_operation();
	_remove_text(p_line, 0, p_line, text[p_line].length());
	_insert_text(p_line, 0, p_new_text);
	for (int i = 0; i < carets.size(); i++) {
		if (get_caret_line(i) == p_line && get_caret_column(i) > p_new_text.length()) {
			set_caret_column(p_new_text.length(), false, i);
		}
		if (has_selection(i) && p_line == get_selection_to_line(i) && get_selection_to_column(i) > text[p_line].length()) {
			carets.write[i].selection.to_column = text[p_line].length();
		}
	}
	end_complex_operation();
}
String TextEdit::get_line(int p_line) const {