### 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(p_frame == nullptr, p_h);
	ERR_FAIL_COND_V(p_line < 0 || p_line >= (int)p_frame->lines.size(), p_h);
	Line &l = p_frame->lines[p_line];
	MutexLock lock(l.text_buf->get_mutex());
	BitField<TextServer::LineBreakFlag> autowrap_flags = TextServer::BREAK_MANDATORY;
	switch (autowrap_mode) {
		case TextServer::AUTOWRAP_WORD_SMART:
			autowrap_flags = TextServer::BREAK_WORD_BOUND | TextServer::BREAK_ADAPTIVE | TextServer::BREAK_MANDATORY;
			break;
		case TextServer::AUTOWRAP_WORD:
			autowrap_flags = TextServer::BREAK_WORD_BOUND | TextServer::BREAK_MANDATORY;
			break;
		case TextServer::AUTOWRAP_ARBITRARY:
			autowrap_flags = TextServer::BREAK_GRAPHEME_BOUND | TextServer::BREAK_MANDATORY;
			break;
		case TextServer::AUTOWRAP_OFF:
			break;
	}
	autowrap_flags = autowrap_flags | TextServer::BREAK_TRIM_EDGE_SPACES;
	
	l.text_buf->clear();
	l.text_buf->set_break_flags(autowrap_flags);
	l.text_buf->set_justification_flags(_find_jst_flags(l.from));
	l.char_offset = *r_char_offset;
	l.char_count = 0;
	
	l.offset.x = _find_margin(l.from, p_base_font, p_base_font_size);
	l.text_buf->set_width(p_width - l.offset.x);
	l.text_buf->set_alignment(_find_alignment(l.from));