fix: get_last_feeding returns most recent FEED_DONE regardless of API order

[jadenv]

Problem

get_last_feeding() stopped returning the correct feeding after the PetSafe API changed the ordering of messages returned by GET /smart-feed/feeders/{id}/messages?days=N.

Previously the API returned messages newest-first, so iterating and returning the first FEED_DONE match was correct. In the last week or so, it seems API silently changed to returning messages oldest-first, causing get_last_feeding() to return a stale feeding from days ago instead of the most recent one.

Example API response (current ordering — oldest first)

[
  {"message_type": "FEED_DONE", "created_at": "2025-04-20T08:00:00Z", "payload": {"time": 1745136000, "amount": 1}},
  {"message_type": "FEED_DONE", "created_at": "2025-04-20T12:00:00Z", "payload": {"time": 1745150400, "amount": 1}},
  {"message_type": "FEED_DONE", "created_at": "2025-04-20T17:00:00Z", "payload": {"time": 1745168400, "amount": 2}}
]

With the old implementation the first FEED_DONE found (8:00 AM) was returned instead of the most recent one (5:00 PM).

Fix

Instead of returning the first FEED_DONE in iteration order, filter to all valid FEED_DONE entries and return the one with the highest payload.time Unix timestamp — making the result correct regardless of what order the API returns messages in the future.

[jadenv]

@ThomasHFWright Any chance we could get this merged soon? Thanks!

[IAmTheMitchell]

I opened (and closed) a duplicate PR before I saw this. My fix was the same.

Would really appreciate if we could get this merged in!