Fix incorrectly triggered end of feed when too many filters are applied

[hjiangsu]

Pull Request Description

This PR fixes an issue where the feed stops fetching for new posts when there are too many filtered/deleted posts which cause the total number of fetched posts to be zero. Instead of determine the end of the feed from the filtered posts, it now uses the original response's length to determine the end of the feed.

Issue Being Fixed

Issue Number: #1592

Screenshots / Recordings

Checklist

• If a new package was added, did you ensure it uses an appropriate license and is actively maintained?
• Did you use localized strings (and added appropriate descriptions) where applicable?
• Did you add semanticLabels where applicable for accessibility?

[micahmo]

@hjiangsu I'm not sure if it's related to this change, but I've started noticing that my feed always displays "No more items to load" at the end (instead of a spinner) before it proceeds to load more items. Here's a recording.

scrcpy_HJbJoWYrlA.mp4