Fetch more than one page when polling stripe events (#19343)

This fixes a bug that was causing most users to be unable to use the
LLMs via Zed. It was caused by not using pagination and, instead, always
querying the very first page of stripe events.

Note that we're also allowing processing events generated in the last 24
hours (before, this was only 1 hour). I did this so that we can process
the backlog of events that the aforementioned bug was skipping.

Release Notes:

- N/A