### Godot version

v4.0.beta13.official [caacade56]

### System information

Linux Ubuntu 20.04 with Unity desktop

### Issue description

When calling an undefined function in the shader editor with argument(s), such as `undefined_function(1)`, the error reads:

> Too many arguments for "undefined_function()" call. Expected at most 0 but received 1.

instead of the expected:

> No matching function found for: 'undefined_function'.

This is possibly a regression introduced in https://github.com/godotengine/godot/issues/18225, since the latter was focused on the arguments part.

To avoid such regression in the future, consider adding a unit test with this case (and, in fact, unit tests for the other signature errors too if there are not already).

### Steps to reproduce

1. Create a shader resource and open the shader editor
2. Enter `undefined_function(1);` in the fragment() definition

### Minimal reproduction project

N/A
if (!arg) {
			return false;
		}
		if (is_const_decl && arg->type == Node::NODE_TYPE_VARIABLE) {
			const VariableNode *var = static_cast<const VariableNode *>(arg);
			if (!var->is_const) {
				_set_error(RTR("Expected constant expression."));
				return false;
			}
		}
		p_func->arguments.push_back(arg);
		tk = _get_token();
		if (tk.type == TK_PARENTHESIS_CLOSE) {
			return true;
		} else if (tk.type != TK_COMMA) {
			
			_set_error(RTR("Expected ',' or ')' after argument."));
			return false;
		}
	}
	return true;
}
bool ShaderLanguage::is_token_operator(TokenType p_type) {
	return (p_type == TK_OP_EQUAL ||
			p_type == TK_OP_NOT_EQUAL ||
			p_type == TK_OP_LESS ||
			p_type == TK_OP_LESS_EQUAL ||
			p_type == TK_OP_GREATER ||
			p_type == TK_OP_GREATER_EQUAL ||
			p_type == TK_OP_AND ||