WebSocketRpcClient's connect leaks memory on failure

[roekatz]

This would happen when retries are enabled.

WebSocketRpcClient.__aenter__ retries connecting indefinitely:

return await retry(**self.retry_config)(self.__connect__)()

If __connect__ keeps failing - memory usage gradually increases (more noticeably when configuring fast retry strategy). This is due to __connect__ not cleaning resources on exceptions:

• The websocket object is not cleaned
• The RpcChannel object is not closed

This was found while debugging: https://github.com/permitio/opal/issues/274

[roekatz]

Fix merged