Add gate node example to the control flow section of flytesnacks

[cosmicBboy]

fixes flyteorg/flyte#3270

[cosmicBboy]

this is blocked by flyteorg/flyte#3461

[eapolinario]

The failure we're seeing is real, I was able to repro it in local sandbox as well:

❯ pwd
/Users/eduardo/repos/flytesnacks/cookbook/core/type_system

❯ pyflyte run --remote structured_dataset.py schema_compatibility_wf --a 3
{"asctime": "2023-03-14 23:51:04,033", "name": "flytekit", "levelname": "WARNING", "message": "FlyteSchema is deprecated, use Structured Dataset instead."}
Failed with Exception: Reason: SYSTEM:Unknown
RPC Failed, with Status: StatusCode.INTERNAL
        details: failed to compile workflow for [resource_type:WORKFLOW project:"flytesnacks" domain:"development" name:"core.type_system.structured_dataset.schema_compatibility_wf" version:"4rTAVVM9xZF2Jilgvc4cOA==" ] with err failed to compile workflow with err Collected Errors: 2
        Error 0: Code: MismatchingTypes, Node Id: n1, Description: Variable [o0] (type [schema:<columns:<name:"Name" type:STRING > columns:<name:"Age" > columns:<name:"Height" > > ]) doesn't match expected type [structured_dataset_type:<columns:<name:"Age" literal_type:<simple:INTEGER > > > ].
        Error 1: Code: ParameterNotBound, Node Id: n1, Description: Parameter not bound [df].

        Debug string UNKNOWN:Error received from peer ipv6:%5B::1%5D:30080 {grpc_message:"failed to compile workflow for [resource_type:WORKFLOW project:\"flytesnacks\" domain:\"development\" name:\"core.type_system.structured_dataset.schema_compatibility_wf\" version:\"4rTAVVM9xZF2Jilgvc4cOA==\" ] with err failed to compile workflow with err Collected Errors: 2\n\tError 0: Code: MismatchingTypes, Node Id: n1, Description: Variable [o0] (type [schema:<columns:<name:\"Name\" type:STRING > columns:<name:\"Age\" > columns:<name:\"Height\" > > ]) doesn\'t match expected type [structured_dataset_type:<columns:<name:\"Age\" literal_type:<simple:INTEGER > > > ].\n\tError 1: Code: ParameterNotBound, Node Id: n1, Description: Parameter not bound [df].\n", grpc_status:13, created_time:"2023-03-14T23:51:05.241902-07:00"}