### 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 (r_constant_value) {
			if (shader->constants[p_identifier].initializer && shader->constants[p_identifier].initializer->values.size() == 1) {
				*r_constant_value = shader->constants[p_identifier].initializer->values[0];
			}
		}
		if (r_type) {
			*r_type = IDENTIFIER_CONSTANT;
		}
		return true;
	}
	for (int i = 0; i < shader->functions.size(); i++) {
		if (!shader->functions[i].callable) {
			continue;
		}
		if (shader->functions[i].name == p_identifier) {
			if (r_data_type) {
				*r_data_type = shader->functions[i].function->return_type;
			}
			if (r_array_size) {
				*r_array_size = shader->functions[i].function->return_array_size;
			}
			if (r_type) {
				*r_type = IDENTIFIER_FUNCTION;
			}
			return true;
		}
	}
	return false;
}
bool ShaderLanguage::_validate_operator(OperatorNode *p_op, DataType *r_ret_type, int *r_ret_size) {