[Synapse] Fix deserialization issue for creating Pipeline/Dataset/Trigger

[wonner]

Description

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[wyunchi-ms]

Could you please offer the diff of these data models such as DataFlow as PSDataFlow.

[wonner]

Could you please offer the diff of these data models such as DataFlow as PSDataFlow.

DataFlow is a model in SDK, it has some subclasses such as MappingDataFlow. In the previous code, we only return the wrapper class PSDataFlow, it will miss the properties in subclass. So we keep align with ADF here, just provided the real data flow sub type. (In ADF, the link is: DataFlow Class (Microsoft.Azure.Management.DataFactory.Models) - Azure for .NET Developers | Microsoft Docs)

[wonner]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).