Resolve #3588038 "Refactor auto save endpoint"

Updates openapi.yml, controller, tests and react code to support auto-saves/pending returning all current auto-save entries in wrapped in a top level data property.

I have not used any AI in this MR, but it seems that @shubham.prakash did, although unclear what tool he used and for what.

Testing instructions

• First step for someone to test the changes in this MR

Closes #3588038