Improve topology map widget documentation

[api-clients-generation-pipeline]

See DataDog/datadog-api-spec#5974 Test branch datadog-api-spec/test/adam.hooper/topology-widget-freshen-2

Behavior change

Solved two small parsing bugs:

oneOf matched both branches

Now, TopologyMapWidgetDefinitionDataStreams has an attribute requests with each child a TopologyRequestDataStreams. And TopologyMapWidgetDefinitionServiceMap has an attribute requests with each child TopologyRequestServiceMap.

When parsing a service-map widget, we test both branches:

• TopologyMapWidgetDefinitionServiceMap => succeeds, because its requests contains a valid TopologyRequestServiceMap
• TopologyMapWidgetDefinitionDataStreams => succeeds in error, because its requests contains an invalid TopologyRequestDataStreams but that _unparsed wasn't propagated to the list.

Fix: propagate _unparsed so the list is marked unparsed.

Formula Events group-by lists failed to parse

#3230 (March 2026) introduced a regression: Formula Events group-by lists failed to parse.

What we wanted:

query.get_oneof_instance()          # -> FormulaAndFunctionEventQueryDefinition
query._unparsed                     # -> False

gb = query.get_oneof_instance().group_by
type(gb)                            # -> list
gb[0].facet                         # -> '@geo.country_iso_code'
gb[0].sort.order.value              # -> 'desc'

What we shipped:

query = <FormulaAndFunctionQueryDefinition>
query.get_oneof_instance()      # -> UnparsedObject   (not the real variant!)
query._unparsed                 # -> True             (but never surfaced)

gb = query.get_oneof_instance().group_by
type(gb)                        # -> list
gb                              # -> [{'facet': ..., 'limit': 250, 'sort': {...}}]  # raw dicts
gb[0].facet                     # -> AttributeError: 'dict' object has no attribute 'facet'

This is because the parser wouldn't accept oneOf where one branch is a list.

But we didn't see this error because we weren't propagating _unparsed correctly.

Fix: deserialize_model(): accept a list as a valid oneOf child.