R1:b09168e689ff

Show "Show Older" for transactions the user has not interacted with

Summary: Fixes T7454. We weren't triggering "Show Older" unless there were hidden events because of a previous interaction.

Test Plan:
- Set page size to 3.
- Viewed a task with ~10 transactions.
- Before patch:
- Only 3 most recent transactions visible, no way to see older ones.
- Saw "show older" appear, paged backward through transaction histroy.
- Also, interacted with task and then viewed it, made sure "show older"…