fix(backfill): chunk up writes to DB (#19699)

## Description

When a given range of transactions generated too many affected object
IDs, the backfill script would stop, because of limits in postgres'
protocol over the wire.

By chunking up the writes into batches of 1000, we avoid hitting this
limit.

## Test plan

Running this backfill against the DBs now -- and it is not crashing.

---

## Release notes

Check each box that your changes affect. If none of the boxes relate to
your changes, release notes aren't required.

For each box you select, include information after the relevant heading
that describes the impact of your changes that a user might notice and
any actions they must take to implement updates.

- [ ] Protocol: 
- [ ] Nodes (Validators and Full nodes): 
- [ ] Indexer: 
- [ ] JSON-RPC: 
- [ ] GraphQL: 
- [ ] CLI: 
- [ ] Rust SDK:
- [ ] REST API:

crates/sui-indexer/src/backfill/backfill_instances/tx_affected_objects.rs

@@ -56,11 +56,13 @@ impl BackfillTask for TxAffectedObjectsBackfill {
             })
             .collect();
 
-        diesel::insert_into(tx_affected_objects::table)
-            .values(&affected_objects)
-            .on_conflict_do_nothing()
-            .execute(&mut conn)
-            .await
-            .unwrap();
+        for chunk in affected_objects.chunks(1000) {
+            diesel::insert_into(tx_affected_objects::table)
+                .values(chunk)
+                .on_conflict_do_nothing()
+                .execute(&mut conn)
+                .await
+                .unwrap();
+        }
     }
 }