### 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_COND(p_event.is_null());
	Ref<InputEventMouseButton> b = p_event;
	if (b.is_valid()) {
		if (ime_text.length() != 0) {
			
			return;
		}
		if (b->is_pressed() && b->get_button_index() == MouseButton::RIGHT && context_menu_enabled) {
			_ensure_menu();
			menu->set_position(get_screen_position() + get_local_mouse_position());
			menu->reset_size();
			menu->popup();
			grab_focus();
			accept_event();
			return;
		}
		if (is_middle_mouse_paste_enabled() && b->is_pressed() && b->get_button_index() == MouseButton::MIDDLE && is_editable() && DisplayServer::get_singleton()->has_feature(DisplayServer::FEATURE_CLIPBOARD_PRIMARY)) {
			String paste_buffer = DisplayServer::get_singleton()->clipboard_get_primary().strip_escapes();
			deselect();
			set_caret_at_pixel_pos(b->get_position().x);
			if (!paste_buffer.is_empty()) {
				insert_text_at_caret(paste_buffer);
				if (!text_changed_dirty) {
					if (is_inside_tree()) {
						MessageQueue::get_singleton()->push_call(this, "_text_changed");
					}
					text_changed_dirty = true;
				}