[Hubs][ADF] Handle complex NetSavings in reservation recommendations parquet conversion

[flanakin]

⚠️ Problem

Cost Management reservation recommendation exports changed their data format, which is breaking CSV to parquet conversion in ADF.

🛠️ Solution

Update the schema file to account for the changed schema.

ℹ️ Additional context

Confirm if this is getting reverted in CM as this may be a breaking change.

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