## Issue Addressed
- Resolves#1080
## Proposed Changes
- Call `update_pubkey_cache` only in the `build_all_caches` method and `get_validator_index` method.
## Additional Info
This does reduce the number of places the cache is updated, making it simpler. But the `get_validator_index` method is used a couple times when we are iterating through the entire validator registry (or set of active validators). Before, we would only call `update_pubkey_cache` once before iterating through all validators. So I'm not _totally_ sure this change is worth it.
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