`block_search` endpoint isn't tested and doesn't work in CI integration tests

[thanethomson]

After merging #991, I realized that I didn't see that the block_search test isn't actually executed during integration testing, and it actually fails when it's enabled.

Steps to reproduce

Add #[tokio::test] before the block_search method in the kvstore integration test.

What's the definition of "done" for this issue?

When all kvstore integration tests pass.