Changes to Per-topic Kafka metadata for the topics list

request property entities/items/entity_type was restricted to a list of enum values

added the new agents enum value to the request property entities/items/entity_type

added the new destinations enum value to the request property entities/items/entity_type

added the new manual enum value to the request property entities/items/entity_type

added the new pipelines enum value to the request property entities/items/entity_type

added the new sources enum value to the request property entities/items/entity_type

added the new transforms enum value to the request property entities/items/entity_type