Register blocks in validator monitor (#3635)
Register blocks in validator monitor (#3635)

## Issue Addressed

Closes #3460

## Proposed Changes

`blocks` and `block_min_delay` are never updated in the epoch summary



Co-authored-by: Michael Sproul <f973abbf0a19f8166c601c53f9d7a897742d9b94@gmail.com>

sigp/lighthouse,sigp/lighthouse,sigp/lighthouse,sigp/lighthouse