[Synapse] Use the Azure.Core.Expressions.DataFactory type replacements

[JoshLove-msft]

Azure.ResourceManager.Synapse currently generates types that we would like to replace with the types from Azure.Core.Expressions.DataFactory. For now we have added a temporary config that can be used to disable the DF type replacement in Azure/autorest.csharp#3553. Because the library is already GA, and we still want to do the type replacements, we will need to:

• move the generated types/API into the convenience layer and EBN
• remove the temporary config that is being added to prevent type replacement from Synapse autorest.md
• let the code gen do the type replacement
• remove the use-core-datafactory-replacements config from autorest.csharp