feat: index Vote reason

[Sekhmet]

Summary

This PR adds indexing for vote reason on both EVM and Starknet APIs.

How to test

1. Run yarn dev:full.
2. Wait for everything to get indexed (you can check _meta block on APIs to see progress or logs for Checkpoint).
3. Run query below on both Checkpoint and Subgraph.
4. Some votes should have reason.

{
  votes {
    metadata {
      reason
    }
  }
}