Intent of buffered_callbacks_lost_when_Update_struct_is_recreated

All 2 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 2 tests
- server/ 2 tests
  - service/ 2 tests
    
    history/ 2 tests
    
    workflow/ 2 tests
    
    update/ 2 tests
    
    TestAttachCallbacks/ 2 tests
    
    go.temporal.io/server/service/history/workflow/update/TestAttachCallbacks/buffered_callbacks_lost_when_Update_struct_is_recreated Introduced here
    
    go.temporal.io/server/service/history/workflow/update/TestAttachCallbacks/same_requestID_can_be_re-buffered_on_new_Update_struct_after_loss Inherited update.go ×1