ctp: remove unnecessary require (#3572)

There was a leftover require from when the contract
was `initializable`. This commit removes that because
it is no longer needed.
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

packages/contracts-periphery/contracts/universal/op-erc721/OptimismMintableERC721Factory.sol

@@ -68,11 +68,6 @@ contract OptimismMintableERC721Factory is Semver {
             "OptimismMintableERC721Factory: L1 token address cannot be address(0)"
         );
 
-        require(
-            bridge != address(0),
-            "OptimismMintableERC721Factory: bridge address must be initialized"
-        );
-
         OptimismMintableERC721 localToken = new OptimismMintableERC721(
             bridge,
             remoteChainId,