[STRATCONN-5380] - Fix google enhanced conversion error parsing

[varadarajan-tw]

This PR fixes HTTP error parsing foruserList for Google Enhanced Conversions destination.

This PR solves two key issues

• Internal Error due to incorrect response structure parsing
• Handles concurrent modification error and rethrows it as retryable error for all APIs used in userList action. It seems like all APIs createOfflineJob, addOpertions and run (less likely) can throw this exception. (Previous PR)

More on before and after state in Test Doc

This destination could benefit from Multistatus. I'll try to implement it in a different PR.

Testing

• Added unit tests for new functionality
• Tested end-to-end using the local server
• [If destination is already live] Tested for backward compatibility of destination. Note: New required fields are a breaking change.
• [Segmenters] Tested in the staging environment
• [Segmenters] [If applicable for this change] Tested for regression with Hadron.