Close open connections for deferrable SFTPSensor

[pankajkoti]

It's observed that running the SFTPSensor in deferrable mode
fails to close opened SSH connections to the server, resulting
in a continuous increase of open connections over time.
This pull request addresses this issue by ensuring that
connections are opened using a context manager, allowing
them to be closed once the relevant data has been read
from the SSH server during file sensing.

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[pankajkoti]

Before this PR, we can see in task logs that there was no close connection called

With this PR, we do send close connection calls

Before this PR, on the SSH server, we can see growing number of connections that just logs that it's accepting connections, but no connection closures received

With this PR, we see connection closures being received and that the count does not keep on accumulating

[fritz-astronomer]

lgtm

[hussein-awala]

The change looks good, I think it is possible to test it by checking if the method __aexit__ (or close if it has one) is called.

However, I wonder why you need # type: ignore[return]? 🤔

[Lee-W]

The change looks good, I think it is possible to test it by checking if the method __aexit__ (or close if it has one) is called.

Yep, this is what we should check and is part of the reason why the tests failed originally. Just fixed it 🔧

However, I wonder why you need # type: ignore[return]? 🤔

Otherwise, we'll encounter error: Missing return statement [return]. Tried a few ways, but didn't find a good enough way to pass it 🤔

[Lee-W]

I also test it locally to verify the functionality. 👍

[sunank200]

LGTM