## Description

Change GraphQL's package store implementation to depend on GraphQL's
`Db` type, instead of `IndexerReader`. This means package loads are
subject to our limits and metrics, and makes it easier to switch them to
using data loaders in future.

## Test plan

Existing tests

## Stack

- #17177 
- #17178 

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## 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: