## Problem
Fix LKB-2632.
The safekeeper wal read path does not seem to retry at all. This would
cause client read errors on the customer side.
## Summary of changes
- Retry on `safekeeper::wal_backup::read_object`.
- Note that this only retries on S3 HTTP connection errors. Subsequent
reads could fail, and that needs more refactors to make the retry
mechanism work across the path.
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Signed-off-by: Alex Chi Z <chi@neon.tech>
dbde37c53a