Moving the newly introducedd errors into ExecutionTracker

contracts/core/GuardableModifier.sol

@@ -90,7 +90,7 @@ abstract contract GuardableModifier is Module, Guardable, Modifier {
         }
     }
 
-    function sentOrSignedBy() private returns (address) {
+    function sentOrSignedBy() private view returns (address) {
         if (modules[msg.sender] != address(0)) {
             return msg.sender;
         }

contracts/core/Modifier.sol

@@ -21,12 +21,6 @@ abstract contract Modifier is
     /// @param sender The address of the sender.
     error NotAuthorized(address sender);
 
-    /// @param hash already executed.
-    error HashAlreadyExecuted(bytes32 hash);
-
-    /// @param hash already executed.
-    error HashInvalidated(bytes32 hash);
-
     /// `module` is invalid.
     error InvalidModule(address module);
 

contracts/signature/ExecutionTracker.sol

@@ -3,6 +3,9 @@ pragma solidity >=0.8.0 <0.9.0;
 
 /// @title ExecutionTracker - A contract that keeps track of executed and invalidated hashes
 contract ExecutionTracker {
+    error HashAlreadyExecuted(bytes32);
+    error HashInvalidated(bytes32);
+
     mapping(address => mapping(bytes32 => bool)) public executed;
     mapping(address => mapping(bytes32 => bool)) public invalidated;