docs: Update README to include eth-json-rpc-middleware in dependency graph

[Mrtenz]

Explanation

This adds eth-json-rpc-middleware to the root README dependency graph.

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes

---

Note

Adds @metamask/eth-json-rpc-middleware to the README packages list and dependency graph with its connections.

• Docs (README):
  • Packages: Add @metamask/eth-json-rpc-middleware to the package list.
  • Dependency graph (mermaid):
    • Add node eth_json_rpc_middleware.
    • Add edges: eth_json_rpc_middleware → eth_block_tracker, eth_json_rpc_provider, json_rpc_engine, error_reporting_service, network_controller.
    • Add edge: network_controller → eth_json_rpc_middleware.

^{Written by Cursor Bugbot for commit c8cf909. This will update automatically on new commits. Configure here.}

[cursor]

Bug: Circular Dependency in Middleware and Controller

The dependency graph now has a circular dependency between eth_json_rpc_middleware and network_controller. This invalidates the graph and can cause issues with dependency resolution and build tools.