### 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)

if (selection.active && selection.from_frame && selection.from_line >= 0 && selection.from_line < (int)selection.from_frame->lines.size()) {
		
		float line_offset = selection.from_frame->lines[selection.from_line].offset.y;
		
		for (int i = 0; i < selection.from_frame->lines[selection.from_line].text_buf->get_line_count(); i++) {
			Vector2i range = selection.from_frame->lines[selection.from_line].text_buf->get_line_range(i);
			if (range.x <= selection.from_char && range.y >= selection.from_char) {
				break;
			}
			line_offset += selection.from_frame->lines[selection.from_line].text_buf->get_line_size(i).y + theme_cache.line_separation;
		}
		
		ItemFrame *it = selection.from_frame;
		while (it->parent_frame != nullptr) {
			line_offset += it->parent_frame->lines[it->line].offset.y;
			it = it->parent_frame;
		}
		vscroll->set_value(line_offset);
	}
}
void RichTextLabel::scroll_to_paragraph(int p_paragraph) {