### Godot version

4.0.2.stable.official [7a0977ce2]

### System information

Windows 10

### Issue description

LineEdit node with enabled "expand_to_text_length" option and "minimum_character_width = 0" and cleared margins in style overrides still has some empty space inside
![node](https://github.com/godotengine/godot/assets/23380802/86c79678-8422-4a98-8406-602edd7dc48b)
![node settings](https://github.com/godotengine/godot/assets/23380802/11d04d71-bbf1-4c16-8155-fe39b5bbd66b)
![style overrides](https://github.com/godotengine/godot/assets/23380802/6b3c3925-b4bd-455b-aac1-ddeb54a4d796)


### Steps to reproduce

1. Add LineEdit node
2. Set expand_to_text_length = true
3. Set minimum_character_width in theme overrides = 0
4. Set normal to StyleBoxEmpty


### Minimal reproduction project

[LineEdit can't be zero sized.zip](https://github.com/godotengine/godot/files/11566017/LineEdit.can.t.be.zero.sized.zip)

if (!selection.enabled && p_shift) {
		selection.start_column = caret_column;
	}
	if (!p_shift) {
		deselect();
	}
}
void LineEdit::shift_selection_check_post(bool p_shift) {
	if (p_shift) {
		selection_fill_at_caret();
	}
}
void LineEdit::set_caret_at_pixel_pos(int p_x) {