### 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)

Item *it = p_frame;
	while (it) {
		ItemFX *ifx = nullptr;
		if (it->type == ITEM_CUSTOMFX || it->type == ITEM_SHAKE || it->type == ITEM_WAVE || it->type == ITEM_TORNADO || it->type == ITEM_RAINBOW || it->type == ITEM_PULSE) {
			ifx = static_cast<ItemFX *>(it);
		}
		if (!ifx) {
			it = _get_next_item(it, true);
			continue;
		}
		ifx->elapsed_time += p_delta_time;
		ItemShake *shake = nullptr;
		if (it->type == ITEM_SHAKE) {
			shake = static_cast<ItemShake *>(it);
		}
		if (shake) {
			bool cycle = (shake->elapsed_time > (1.0f / shake->rate));
			if (cycle) {
				shake->elapsed_time -= (1.0f / shake->rate);
				shake->reroll_random();
			}
		}
		it = _get_next_item(it, true);
	}
}
int RichTextLabel::_find_first_line(int p_from, int p_to, int p_vofs) const {