### 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)

ERR_FAIL_COND_V(!selection.enabled, false);
	if (p_string.size() == 0) {
		selection.active = false;
		return false;
	}
	int char_idx = p_search_previous ? -1 : 0;
	int current_line = 0;
	int to_line = main->first_invalid_line.load();
	int ending_line = to_line - 1;
	if (p_from_selection && selection.active) {
		
		char_idx = p_search_previous ? selection.from_char - 1 : selection.to_char;