## Problem
See
https://neondb.slack.com/archives/C03QLRH7PPD/p1723038557449239?thread_ts=1722868375.476789&cid=C03QLRH7PPD
Logical replication subscription by default use `synchronous_commit=off`
which cause problems with safekeeper
## Summary of changes
Set `synchronous_commit=on` for logical replication subscription in
test_subscriber_restart.py
## Checklist before requesting a review
- [ ] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.
## Checklist before merging
- [ ] Do not forget to reformat commit message to not include the above
checklist
---------
Co-authored-by: Konstantin Knizhnik <knizhnik@neon.tech>
Co-authored-by: Heikki Linnakangas <heikki@neon.tech>
cbe8c77997