[main][GraphQL] Fix pruning compatibility issues (#18862)

## Description 

Two further fixes to get GraphQL working with pruned databases.

Cherry-pick of #18860 **into main**.

## Test plan 

Tested by deploying this version of the service against a pruned DB, and
ensuring the following query executed successfully:

```graphql
query {
  chainIdentifier
  protocolConfig(protocolVersion: 10) {
    featureFlags {
      key
      value
    }
  }
}
```

---

## 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: 
- [x] GraphQL: Adds support for running GraphQL against a pruned version
of the service.
- [ ] CLI: 
- [ ] Rust SDK:
- [ ] REST API:

crates/sui-graphql-rpc/src/types/protocol_config.rs

@@ -3,7 +3,7 @@
 
 use async_graphql::*;
 use diesel::{ExpressionMethods, QueryDsl};
-use sui_indexer::schema::{checkpoints, epochs};
+use sui_indexer::schema::{chain_identifier, epochs};
 use sui_protocol_config::{ProtocolConfig as NativeProtocolConfig, ProtocolVersion};
 
 use crate::{
@@ -90,7 +90,7 @@ impl ProtocolConfigs {
 
 impl ProtocolConfigs {
     pub(crate) async fn query(db: &Db, protocol_version: Option<u64>) -> Result<Self, Error> {
-        use checkpoints::dsl as c;
+        use chain_identifier::dsl as c;
         use epochs::dsl as e;
 
         let (latest_version, digest_bytes): (i64, Option<Vec<u8>>) = db
@@ -99,9 +99,8 @@ impl ProtocolConfigs {
                     e::epochs
                         .select((
                             e::protocol_version,
-                            c::checkpoints
+                            c::chain_identifier
                                 .select(c::checkpoint_digest)
-                                .filter(c::sequence_number.eq(0))
                                 .single_value(),
                         ))
                         .order_by(e::epoch.desc())

crates/sui-indexer/src/schema/pg.rs

@@ -296,14 +296,11 @@ macro_rules! for_all_tables {
             display,
             epochs,
             events,
-            events_partition_0,
             objects,
             objects_history,
-            objects_history_partition_0,
             objects_snapshot,
             packages,
             transactions,
-            transactions_partition_0,
             tx_calls,
             tx_changed_objects,
             tx_digests,