Don't attempt to register validators that are pre-activation (#3441)
Don't attempt to register validators that are pre-activation (#3441)

## Issue Addressed

https://github.com/sigp/lighthouse/issues/3440

## Proposed Changes

Don't consider pre-activation validators for validator registration. 



Co-authored-by: sean <73195634d109c8d8533133f62102413ab6837100@gmail.com>
Co-authored-by: Michael Sproul <f973abbf0a19f8166c601c53f9d7a897742d9b94@gmail.com>

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