### 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 (undo_stack_pos == nullptr) {
		return undo_stack.size() > 1;
	}
	return undo_stack_pos != undo_stack.front();
}
bool LineEdit::has_redo() const {
	return undo_stack_pos != nullptr && undo_stack_pos != undo_stack.back();
}
void LineEdit::undo() {
	if (!editable) {
		return;
	}
	if (undo_stack_pos == nullptr) {
		if (undo_stack.size() <= 1) {
			return;
		}
		undo_stack_pos = undo_stack.back();
	} else if (undo_stack_pos == undo_stack.front()) {
		return;
	}
	deselect();
	undo_stack_pos = undo_stack_pos->prev();
	TextOperation op = undo_stack_pos->get();
	text = op.text;
	scroll_offset = op.scroll_offset;
	set_caret_column(op.caret_column);
	_shape();
	_emit_text_change();
}
void LineEdit::redo() {