### Godot version

4.0-rc1

### System information

Windows 10

### Issue description

The code: `@export @onready var camera_system : Node3D`

Is throwing: `Line 5:The "@onready" annotation will make the default value to be set after the "@export" takes effect and will override it. (Warning treated as error.)` and is crashing the game.

Unchecking "Treat Warning as Errors" seems to have no effect:

![imagen](https://user-images.githubusercontent.com/248383/217900756-8e214c40-68fb-4fb2-8509-a1e689725930.png)

![imagen](https://user-images.githubusercontent.com/248383/217901253-3b758ebc-48e9-40fe-8d77-16fce7cbae88.png)


### Steps to reproduce

- Write `@export @onready var some_var : Node3D`
- In Project Settings, uncheck `Treat Warning as Errors`
- Try to run the project, a `Parser Error` will be thrown.

### Minimal reproduction project

It's as simple as adding one line of code, so I'm not sure a MRP is needed.
break;
		}
		String doc_line = comments[line].comment.trim_prefix("##");
		in_codeblock = _in_codeblock(doc_line, in_codeblock, &codeblock_begins);
		if (in_codeblock) {
			int i = 0;
			for (; i < codeblock_begins; i++) {
				if (doc_line[i] != ' ') {
					break;
				}
			}
			doc_line = doc_line.substr(i);
		} else {
			doc_line = doc_line.strip_edges();
		}
		String line_join = (in_codeblock) ? "\n" : " ";
		doc = (doc.is_empty()) ? doc_line : doc + line_join + doc_line;
		line++;
	}
	return doc;
}
void GDScriptParser::get_class_doc_comment(int p_line, String &p_brief, String &p_desc, Vector<Pair<String, String>> &p_tutorials, bool p_inner_class) {
	const HashMap<int, GDScriptTokenizer::CommentData> &comments = tokenizer.get_comments();
	if (!comments.has(p_line)) {
		return;
	}
	ERR_FAIL_COND(!p_brief.is_empty() || !p_desc.is_empty() || p_tutorials.size() != 0);
	int line = p_line;
	bool in_codeblock = false;
	enum Mode {