feat: event on setAvs

Author: stevennevins

src/SlashingRegistryCoordinator.sol

@@ -934,6 +934,8 @@ contract SlashingRegistryCoordinator is
     function _setAVS(
         address _avs
     ) internal {
+        address prevAVS = avs;
+        emit AVSUpdated(prevAVS, _avs);
         avs = _avs;
     }
 

src/interfaces/ISlashingRegistryCoordinator.sol

@@ -190,6 +190,13 @@ interface ISlashingRegistryCoordinatorEvents is ISlashingRegistryCoordinatorType
      */
     event ChurnApproverUpdated(address prevChurnApprover, address newChurnApprover);
 
+    /**
+     * @notice Emitted when the AVS address is updated.
+     * @param prevAVS The previous AVS address.
+     * @param newAVS The new AVS address.
+     */
+    event AVSUpdated(address prevAVS, address newAVS);
+
     /**
      * @notice Emitted when the ejector address is updated.
      * @dev Emitted in _setEjector().

test/unit/SlashingRegistryCoordinatorUnit.t.sol

@@ -567,6 +567,14 @@ contract SlashingRegistryCoordinator_SetAVS is SlashingRegistryCoordinatorUnitTe
         vm.prank(address(0xdead));
         slashingRegistryCoordinator.setAVS(newAVS);
     }
+
+    function test_emitsAVSUpdatedEvent() public {
+        vm.expectEmit(true, true, true, true);
+        emit AVSUpdated(serviceManager, newAVS);
+
+        vm.prank(proxyAdminOwner);
+        slashingRegistryCoordinator.setAVS(newAVS);
+    }
 }
 
 contract SlashingRegistryCoordinator_CreateSlashableStakeQuorum is