### 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)

} else if (subtag_a[0] == "margins") {
						Vector<String> subtag_b = subtag_a[1].split(",");
						_normalize_subtags(subtag_b);
						if (subtag_b.size() == 4) {
							dropcap_margins.position.x = subtag_b[0].to_float();
							dropcap_margins.position.y = subtag_b[1].to_float();
							dropcap_margins.size.x = subtag_b[2].to_float();
							dropcap_margins.size.y = subtag_b[3].to_float();
						}
					} else if (subtag_a[0] == "outline_size") {
						outline_size = subtag_a[1].to_int();
					} else if (subtag_a[0] == "color") {
						color = Color::from_string(subtag_a[1], color);
					} else if (subtag_a[0] == "outline_color") {
						outline_color = Color::from_string(subtag_a[1], outline_color);
					}
				}
			}
			int end = p_bbcode.find("[", brk_end);
			if (end == -1) {
				end = p_bbcode.length();
			}
			String dc_txt = p_bbcode.substr(brk_end + 1, end - brk_end - 1);
			push_dropcap(dc_txt, f, fs, dropcap_margins, color, outline_size, outline_color);
			pos = end;
			tag_stack.push_front(bbcode_name);
		} else if (tag.begins_with("img")) {
			int alignment = INLINE_ALIGNMENT_CENTER;
			if (tag.begins_with("img=")) {
				Vector<String> subtag = tag.substr(4, tag.length()).split(",");