Multibase term value is not properly compressed when using @vocab

[filip26]

Hi,
please try this example:
context:

{
    "@context": {
        "@vocab": "https://w3id.org/security#",
        "value": { "@type": "multibase" }
    }
}

document:

{
    "@context": "https://.../0012-context.jsonld",
    "value": "z4mAs9uHU16jR4xwPcbhHyRUc6BbaiJQE5MJwn3PCWkRXsriK9AMrQQMbjzG9XXFPNgngmQXHKUz23WRSu9jSxPCF"
}

the expected output is

[{ 0: https://..../0012-context.jsonld, 100: [0x7A,0xBC,0x24,0x3F, ... 65 bytes] }]

but got:

[{ 0: https://.../0012-context.jsonld, 100: z4mAs9uHU16jR4xwPcbhHyRUc6BbaiJQE5MJwn3PCWkRXsriK9AMrQQMbjzG9XXFPNgngmQXHKUz23WRSu9jSxPCF }]

[dlongley]

I think this should be covered now, but we should add a test (if we don't have one) to ensure it works properly.