bugfix: allow federation sources to fail #575

Test case:

1. Code

<sib-display
  data-src="sources.jsonld"
  fields="username"
></sib-display>

2. Data

// sources.jsonld
{
  "@id": "sources.jsonld",
  "@type": "ldp:Container",
  "ldp:contains": [
    {
      "federation": "users",
      "@id": "users-paris.jsonld", // change it to "test" to make it fail
      "@type": "ldp:Container"
    },
    {
      "federation": "users",
      "@id": "users-nantes.jsonld",
      "@type": "ldp:Container"
    }
  ],
  "@context": "https://cdn.happy-dev.fr/owl/hdcontext.jsonld"
}

// users-paris.jsonld
{
  "@id": "users-paris.jsonld",
  "@type": "ldp:Container",
  "ldp:contains": [
    {
      "@id": "https://api.test-paris.happy-dev.fr/users/alex_b/",
      "username": "User 1 from Paris"
    },
    {
      "@id": "https://api.test-paris.happy-dev.fr/users/alex_paris_hd/circles/",
      "username": "User 2 from Paris"
    }
  ],
  "@context": "https://cdn.happy-dev.fr/owl/hdcontext.jsonld"
}

// users-nantes.jsonld
{
  "@id": "users-nantes.jsonld",
  "@type": "ldp:Container",
  "ldp:contains": [
    {
      "@id": "https://api.test-nantes.happy-dev.fr/users/alex_b/",
      "username": "User 1 from Nantes"
    },
    {
      "@id": "https://api.test-nantes.happy-dev.fr/users/alex_nantes_hd/circles/",
      "username": "User 2 from Nantes"
    }
  ],
  "@context": "https://cdn.happy-dev.fr/owl/hdcontext.jsonld"
}

When you load the first time, you should see 4 users, from Paris and Nantes.

Change the @id of one container in sources.jsonld. You'll get a 404, but you should still be able to see 2 users from the other container