Use add_validator_to_registry in whisk (#3486)

specs/_features/whisk/beacon-chain.md

@@ -415,38 +415,21 @@ def get_initial_tracker(k: BLSFieldElement) -> WhiskTracker:
 ```
 
 ```python
-def apply_deposit(state: BeaconState,
-                  pubkey: BLSPubkey,
-                  withdrawal_credentials: Bytes32,
-                  amount: uint64,
-                  signature: BLSSignature) -> None:
-    validator_pubkeys = [validator.pubkey for validator in state.validators]
-    if pubkey not in validator_pubkeys:
-        # Verify the deposit signature (proof of possession) which is not checked by the deposit contract
-        deposit_message = DepositMessage(
-            pubkey=pubkey,
-            withdrawal_credentials=withdrawal_credentials,
-            amount=amount,
-        )
-        domain = compute_domain(DOMAIN_DEPOSIT)  # Fork-agnostic domain since deposits are valid across forks
-        signing_root = compute_signing_root(deposit_message, domain)
-        # Initialize validator if the deposit signature is valid
-        if bls.Verify(pubkey, signing_root, signature):
-            index = get_index_for_new_validator(state)
-            validator = get_validator_from_deposit(pubkey, withdrawal_credentials, amount)
-            set_or_append_list(state.validators, index, validator)
-            set_or_append_list(state.balances, index, amount)
-            set_or_append_list(state.previous_epoch_participation, index, ParticipationFlags(0b0000_0000))
-            set_or_append_list(state.current_epoch_participation, index, ParticipationFlags(0b0000_0000))
-            set_or_append_list(state.inactivity_scores, index, uint64(0))
-            # [New in Whisk]
-            k = get_unique_whisk_k(state, ValidatorIndex(len(state.validators) - 1))
-            state.whisk_trackers.append(get_initial_tracker(k))
-            state.whisk_k_commitments.append(get_k_commitment(k))
-    else:
-        # Increase balance by deposit amount
-        index = ValidatorIndex(validator_pubkeys.index(pubkey))
-        increase_balance(state, index, amount)
+def add_validator_to_registry(state: BeaconState,
+                              pubkey: BLSPubkey,
+                              withdrawal_credentials: Bytes32,
+                              amount: uint64) -> None:
+    index = get_index_for_new_validator(state)
+    validator = get_validator_from_deposit(pubkey, withdrawal_credentials, amount)
+    set_or_append_list(state.validators, index, validator)
+    set_or_append_list(state.balances, index, amount)
+    set_or_append_list(state.previous_epoch_participation, index, ParticipationFlags(0b0000_0000))
+    set_or_append_list(state.current_epoch_participation, index, ParticipationFlags(0b0000_0000))
+    set_or_append_list(state.inactivity_scores, index, uint64(0))
+    # [New in Whisk]
+    k = get_unique_whisk_k(state, ValidatorIndex(len(state.validators) - 1))
+    state.whisk_trackers.append(get_initial_tracker(k))
+    state.whisk_k_commitments.append(get_k_commitment(k)) 
 ```
 
 ### `get_beacon_proposer_index`