fix: Python client is currently leaking resources since the aiohttp client isn't closed

[kevjumba]

Summary (What and Why)

Seeing this error when using python client

Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x10593c3a0>
Unclosed connector
connections: ['[(<aiohttp.client_proto.ResponseHandler object at 0x1059589a0>, 0.358368791)]']
connector: <aiohttp.connector.TCPConnector object at 0x1049475b0>

Fixed the issue.

Test Plan

Release Plan

GitHub Issue:

https://github.com/tecton-ai/tecton-http-client-python/issues/XXX

[chrisjordansquire]

@kevjumba - Is this PR still active, or can we close it?