Issue activity past first 100 are not visible on issue details page

### Environment

SaaS (https://sentry.io/)

### Steps to Reproduce

1. Find an issue with >100 activity records (`sentry_activity`)
2. Try to view the earliest activity

### Expected Result

Earliest activity is visible.

### Actual Result

Earliest activity is not visible.

### Product Area

Issues

### Link

_No response_

### DSN

_No response_

### Version

_No response_

Start by reproducing the issue in the Sentry SaaS issue details page with an issue containing more than 100 sentry_activity records, then trace how activity records are loaded and displayed. Done means the earliest activity is visible, not just the most recent 100 records.

Written by the indexing model from the issue text.