Fix SamsungTVWS mocking in samsungtv tests

[epenet]

Proposed change

Ensure the __enter__ method mock returns the correct object, so that we can apply further patching outside of the fixture.

As per https://github.com/xchwarze/samsung-tv-ws-api/blob/d539372cb7dc93e7b94bb3fdf5cc57f585b69e45/samsungtvws/remote.py#L36

class SamsungTVWS:
    ...

    def __enter__(self):
        return self

Needed for #66651

Type of change

• Dependency upgrade
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[probot-home-assistant]

Hey there @escoand, @chemelli74, mind taking a look at this pull request as it has been labeled with an integration (samsungtv) you are listed as a code owner for? Thanks!
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