VecFixed now take sub, align ext with UInt (#1909)

* Allow nested definitions for fixed arrays

* Comment nested test

* Don't import U8aFixed + u8

packages/metadata/src/Metadata/util/validateTypes.ts

@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import { Registry, TypeDef, TypeDefInfo, TypeDefExtVecFixed } from '@polkadot/types/types';
+import { Registry, TypeDef, TypeDefInfo } from '@polkadot/types/types';
 
 import { getTypeDef } from '@polkadot/types/create';
 
@@ -20,10 +20,8 @@ function extractTypes (types: string[]): any[] {
       case TypeDefInfo.Compact:
       case TypeDefInfo.Option:
       case TypeDefInfo.Vec:
-        return extractTypes([(decoded.sub as TypeDef).type]);
-
       case TypeDefInfo.VecFixed:
-        return extractTypes([(decoded.ext as TypeDefExtVecFixed).type]);
+        return extractTypes([(decoded.sub as TypeDef).type]);
 
       case TypeDefInfo.BTreeMap:
       case TypeDefInfo.BTreeSet: