Add field constraint indicator for uniqueItems

[miqh]

Hello,

Fixes #1353.

Schemas which define uniqueItems should now generate a field constraint indicator.

For the example provided in the linked issue, the visual output looks like the following:

---

I also noticed ArraySchema tries to indicate array-type constraints. Specifically, it only covers the minItems and maxItems constraints.

redoc/src/components/Schema/ArraySchema.tsx

Line 21 in 1fdfd13

const minMaxItems = humanizeConstraints(itemConstraintSchema(itemsSchema.schema.minItems, itemsSchema.schema.maxItems));

I haven't dug too deeply into this, but with a simple schema such as:

type: array
  items:
    type: number
  minItems: 1

I'd expect to see something like the following (based on the code), but I don't:

Anyway, I'm happy to follow-up and do something about the latter if it's indeed unexpected behaviour.

[RomanHotsiy]

LGTM