Allow + in search param of word registry

[davidyuk]

Current behavior:

$ curl https://testnet.superhero.aeternity.art/tokenCache/wordRegistry\?search\=yatt+2
{"message":"Parameter 'search' must be url encoded. Its value may not contain reserved characters.","errors":[{"path":".query.search","message":"Parameter 'search' must be url encoded. Its value may not contain reserved characters."}]}%

Seems that it is correct to use + in query, at least URL class encodes it this way:

const u = new URL('https://testnet.superhero.aeternity.art/tokenCache/wordRegistry');
u.searchParams.set('search', 'yatt 2');
u.toString();
// 'https://testnet.superhero.aeternity.art/tokenCache/wordRegistry?search=yatt+2'

as a workaround proposing to set allowReserved: true as proposed in cdimascio/express-openapi-validator#300