fix(#258): stop calling .json() on parsed cleaning/filter reset responses

[SAY-5]

Proposed change:

set_cleaning_reset and set_filter_reset still call .json() on the value returned by session.post, but PetLibroSession.request already returns the parsed data payload (and raises PetLibroAPIError on a non-zero code), so pressing Cleaning Reset or Filter Reset on the Dockstream fountain fails with 'dict' object has no attribute 'json'. Return the parsed payload directly, same as the other reset calls after #201.

Closes #258

Type of change:

• New device.
• Bug fix (non-breaking change which fixes an issue).
• New feature or enhancement (non-breaking change which adds functionality).
• Documentation only.
• Other (please explain).

Checklist:

• If applicable, I have added corresponding documentation changes.
• If applicable, I have reviewed the feature / enhancement guidlines before submitting my request.
• If applicable, I have tested my code for new features & regressions on the latest version of Home Assistant.

Additional notes:

I do not own a PLWF105, so this is verified against the request path in api.py rather than on hardware.