Error handling for NS API is broken

[HippoProgrammer]

Line 50-55 of src/customio/ns.py:

                    self.rate_limited = True
                    raise HTTPResponseException(f'Error {response.status}: {response.reason}. NS API rate limited. No retry will be attempted.')
                    headers = response.headers
                    await asyncio.sleep(int(headers['Retry-After']))
                    self.rate_limited = False

Every line after the raise will not be executed even if the Exception is caught and handled. A migration to warnings should be considered.