daf7 with schemaValidation on can't use universal resolver

[mirceanis]

Bug severity
3

Describe the bug
When using DafResolverUniversal, the DID documents are formatted closer to did core spec (they have @context as array of strings)
This causes failures with INVALID_TYPE errors when resolving DIDs

To Reproduce

import { DafUniversalResolver } from 'daf-resolver-universal'
import { createAgent, IResolver } from 'daf-core'
;(async ()=>{
  const agent = createAgent<IResolver>({
    schemaValidation: true,
    plugins: [
      new DafUniversalResolver({ url: 'https://dev.uniresolver.io/1.0/identifiers/'}),
      //...
    ],
  })
    const doc = await agent.resolveDid({ didUrl: 'did:key:z6Mkfriq1MqLBoPWecGoDLjguo1sB9brj6wT3qZ5BxkKpuP6' })
})();

Expected behaviour
A doc is returned

Observed behaviour
INVALID_TYPE error is thrown

Additional context
The data types in question are imported from did-resolver, sometimes indirectly through did-jwt.
The latest versions of both these libraries have fixed these definitions.

Versions (please complete the following information):

• Daf: 7.0.0-beta.55

[mirceanis]

closed in #293