### Godot version

v4.1.stable.official [970459615]

### System information

Godot v4.1.stable - Windows 10.0.22621 - Vulkan (Forward+) - dedicated NVIDIA GeForce MX330 (NVIDIA; 30.0.15.1169) - 11th Gen Intel(R) Core(TM) i5-1135G7 @ 2.40GHz (8 Threads)

### Issue description

Calling `RichTextLabel`'s `select_all` method has no visual indicator, but it must have one. 

### Steps to reproduce

- Add `RichTextLabel` node
- Set `selection_enabled` value to be `true`
- Call `$RichTextLabel.select_all() `method in `_ready`

### Minimal reproduction project

[RichTextLabel_bug.zip](https://github.com/godotengine/godot/files/12098913/RichTextLabel_bug.zip)

accept_event();
			}
		}
	}
	Ref<InputEventMouseMotion> m = p_event;
	if (m.is_valid()) {
		ItemFrame *c_frame = nullptr;
		int c_line = 0;
		Item *c_item = nullptr;
		int c_index = 0;
		bool outside;
		_find_click(main, m->get_position(), &c_frame, &c_line, &c_item, &c_index, &outside, false);
		if (selection.click_item && c_item) {
			selection.from_frame = selection.click_frame;
			selection.from_line = selection.click_line;
			selection.from_item = selection.click_item;
			selection.from_char = selection.click_char;
			selection.to_frame = c_frame;
			selection.to_line = c_line;
			selection.to_item = c_item;
			selection.to_char = c_index;
			bool swap = false;
			if (selection.click_frame && c_frame) {
				const Line &l1 = c_frame->lines[c_line];
				const Line &l2 = selection.click_frame->lines[selection.click_line];
				if (l1.char_offset + c_index < l2.char_offset + selection.click_char) {
					swap = true;
				} else if (l1.char_offset + c_index == l2.char_offset + selection.click_char) {
					deselect();
					return;