fix(ctb): Add auth to guard checkAfterExecution

Also added regression tests.

packages/contracts-bedrock/src/Safe/LivenessGuard.sol

@@ -60,10 +60,11 @@ contract LivenessGuard is ISemver, BaseGuard {
         address gasToken,
         address payable refundReceiver,
         bytes memory signatures,
-        address
+        address msgSender
     )
         external
     {
+        msgSender; // silence unused variable warning
         require(msg.sender == address(SAFE), "LivenessGuard: only Safe can call this function");
 
         // Cache the set of owners prior to execution.
@@ -105,6 +106,7 @@ contract LivenessGuard is ISemver, BaseGuard {
     ///      1. Add new owners to the lastLive mapping
     ///      2. Delete removed owners from the lastLive mapping
     function checkAfterExecution(bytes32, bool) external {
+        require(msg.sender == address(SAFE), "LivenessGuard: only Safe can call this function");
 
         // Get the current set of owners
         address[] memory ownersAfter = SAFE.getOwners();

packages/contracts-bedrock/test/LivenessGuard.t.sol

@@ -40,6 +40,25 @@ contract LivenessGuard_Getters_Test is LivnessGuard_TestInit {
     }
 }
 
+contract LivnessGuard_CheckTx_TestFails is LivnessGuard_TestInit {
+    function test_checkTransaction_callerIsNotSafe_revert() external {
+        vm.expectRevert("LivenessGuard: only Safe can call this function");
+        livenessGuard.checkTransaction({
+            to: address(0),
+            value: 0,
+            data: hex"00",
+            operation: Enum.Operation.Call,
+            safeTxGas: 0,
+            baseGas: 0,
+            gasPrice: 0,
+            gasToken: address(0),
+            refundReceiver: payable(address(0)),
+            signatures: hex"00",
+            msgSender: address(0)
+        });
+    }
+}
+
 contract LivnessGuard_CheckTx_Test is LivnessGuard_TestInit {
     using SafeTestLib for SafeInstance;
 
@@ -63,6 +82,15 @@ contract LivnessGuard_CheckTx_Test is LivnessGuard_TestInit {
     }
 }
 
+contract LivnessGuard_CheckAfterExecution_TestFails is LivnessGuard_TestInit {
+    function test_checkAfterExecution_callerIsNotSafe_revert() external {
+        vm.expectRevert("LivenessGuard: only Safe can call this function");
+        livenessGuard.checkAfterExecution(bytes32(0), false);
+    }
+}
+
+contract LivnessGuard_CheckAfterExecution_Test is LivnessGuard_TestInit { }
+
 contract LivenessGuard_ShowLiveness_Test is LivnessGuard_TestInit {
     function test_showLiveness_succeeds() external {
         // Cache the caller