fix: onWithdrawalCredentialsChanged should not clean the queue (#396)

src/CSModule.sol

@@ -863,16 +863,17 @@ contract CSModule is
     }
 
     /// @inheritdoc IStakingModule
-    /// @dev Wipes out the queue
-    /// @dev Changing the WC means that the current deposit data in the queue is not valid anymore and can't be deposited
-    ///      So, the key removal charge should be reset to 0 to allow Node Operators to remove the keys without any charge.
+    /// @dev Does nothing
+    /// @dev Changing the WC means that the current deposit data in the queue is not valid anymore and can't be deposited.
+    ///      DSM will unvet current keys.
+    ///      The key removal charge should be reset to 0 to allow Node Operators to remove the keys without any charge.
     ///      After keys removal the DAO should set the new key removal charge.
     function onWithdrawalCredentialsChanged()
         external
         onlyRole(STAKING_ROUTER_ROLE)
     {
-        // skip all existing queue batches to effectively wipe out the queue
-        depositQueue.head = depositQueue.tail;
+        // solhint-disable-previous-line no-empty-blocks
+        // Nothing to do. The key removal charge should be reset separately to 0 to allow Node Operators to remove the keys without any charge.
     }
 
     /// @inheritdoc IStakingModule

test/CSModule.t.sol

@@ -2726,14 +2726,6 @@ contract CsmChangeNodeOperatorRewardAddress is CSMCommon {
     }
 }
 
-contract CsmOnWithdrawalCredentialsChanged is CSMCommon {
-    function test_onWithdrawalCredentialsChanged() public assertInvariants {
-        csm.onWithdrawalCredentialsChanged();
-
-        // TODO: Add queue assert
-    }
-}
-
 contract CsmVetKeys is CSMCommon {
     function test_vetKeys_OnUploadKeys() public assertInvariants {
         uint256 noId = createNodeOperator(2);