When an object schema uses oneOf, the readOnly/writeOnly properties are being ignored

[olivierbeaulieu]

Given this schema:

sampleObject(
      {
        properties: {
          a: { type: 'string' },
          b: {
            type: 'object',
            oneOf: [
              {
                type: 'object',
                properties: {
                  c: {
                    type: 'string',
                  },
                },
              },
              {
                type: 'object',
                properties: {
                  d: {
                    type: 'string',
                  },
                },
              },
            ],
            readOnly: true,
          },
        },
      },
      { skipReadOnly: true }
    )

the readOnly property on the top-level object is being ignored, and the property b will be returned in the schema. It should not, since it is readonly.

[RomanHotsiy]

Closed in #130