Address issue with PATCH payload and complex attributes on the extension schemas

[aerodynamik]

Issue

We have an extension schema that uses complex type attributes and currently PATCH requests fail if operation payload features path key pointing to such attribute instead of referring to it as part of value payload, i.e.:

{
  op: "replace",
  path: "urn:ietf:params:scim:schemas:extension:my_cool_schema:1.0:User:my_complex_attribute",
  value: {
    sub_attribute_1: "oh",
    sub_attribute_2: "no"
  }
}

The issue is with attributes map for this case where an additional lookup for the extension schema is needed.

Note

I decided to add temporary extension schema in spec to test this case in isolation, but otherwise requires updating a lot in specs.

[pond]

Nice. Thanks for the excellent test coverage especially - and noticing the bug in the existing shared example which wasn't taking the "operation" parameter!