Suggestion: Cache the Result of keccak256 in Validator Addition

[swarna1101]

In the current addValidators method, the public key hash is computed multiple times using keccak256. Can we make this change:

Current:

bytes32 pubKeyHash = keccak256(abi.encodePacked(compressedPubKey));

To:

Cache the result of keccak256 once and reuse it across operations.

bytes32 pubKeyHash = _getPublicKeyHash(compressedPubKey);

[AnshuJalan]

This is already done on the main repo.