abi-gen: fix bug w/ 2D arrays of UDT's in Python

Fix bug in handling 2-dimensional arrays of user defined data types in
generated Python code.

packages/abi-gen/src/utils.ts

@@ -195,7 +195,7 @@ export const utils = {
             return tuple.internalType
                 .replace('struct ', '')
                 .replace('.', '')
-                .replace('[]', '');
+                .replace(/\[\]/g, '');
         } else {
             const tupleComponents = tuple.components;
             const lengthOfHashSuffix = 8;

packages/abi-gen/test-cli/fixtures/contracts/AbiGenDummy.sol

@@ -138,6 +138,8 @@ contract AbiGenDummy
     }
 
     function methodReturningArrayOfStructs() public pure returns(Struct[] memory) {}
+    function methodAcceptingArrayOfStructs(Struct[] memory) public pure {}
+    function methodAcceptingArrayOfArrayOfStructs(Struct[][] memory) public pure {}
 
     struct NestedStruct {
         Struct innerStruct;