fix: move IERC20Solady into vendor folder (#11945)

An additional "dependency" folder was added in a recent PR, this
is the same purpose as the "vendor" folder so the interface added
in that PR can simply be moved to the "vendor" folder instead.

packages/contracts-bedrock/src/L2/interfaces/IOptimismSuperchainERC20.sol

 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.0;
 
-import { IERC20Solady } from "src/dependency/interfaces/IERC20Solady.sol";
-import { ISuperchainERC20Extensions, ISuperchainERC20Errors } from "./ISuperchainERC20.sol";
+// Interfaces
+import { IERC20Solady } from "src/vendor/interfaces/IERC20Solady.sol";
+import { ISuperchainERC20Extensions, ISuperchainERC20Errors } from "src/L2/interfaces/ISuperchainERC20.sol";
 
 /// @title IOptimismSuperchainERC20Extension
 /// @notice This interface is available on the OptimismSuperchainERC20 contract.

packages/contracts-bedrock/src/L2/interfaces/ISuperchainERC20.sol

 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.0;
 
-import { IERC20Solady } from "src/dependency/interfaces/IERC20Solady.sol";
+// Interfaces
+import { IERC20Solady } from "src/vendor/interfaces/IERC20Solady.sol";
 
 /// @title ISuperchainERC20Extensions
 /// @notice Interface for the extensions to the ERC20 standard that are used by SuperchainERC20.