Improve error message when schema doesn't match

[sidvishnoi]

As an example, when creating a grant request, the access_token can have 3 options: access-incoming, access-outgoing and access-quote.

Use type: "outgoing-payment" there, but forget to provide the identifier field. Now schema won't match access-outgoing anymore.

Expected error: field identifier is required with type: "outgoing-payment"
Received error: body.access_token.access.0.type must be equal to one of the allowed values

So, missing identifier switched schema to be access-quote (as it's only option without this field), but then it expected type to be "quote", hence the incorrect error message.

Same problem can extend to other request bodies.

[sidvishnoi]

Another instance that happened today:

In limits.debitAmount, pass value: 1000 instead of value: "1000".
Received error: body.access_token.access.0.type must be equal to one of the allowed values,
Expected: invalid type for limits.debitAmount (expected string, received number)