## What changed?
Add StartTime and IsRetentionDelete to delete visibility task
## Why?
Additional info for delete visibility task that might be useful for
implementing VisibilityStore.
## How did you test it?
- [x] built
- [ ] run locally and tested manually
- [ ] covered by existing tests
- [ ] added new unit test(s)
- [ ] added new functional test(s)
## Potential risks