Intent of failed, scheduled-failed

All 4 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 4 tests
- server/ 4 tests
  - components/ 4 tests
    
    nexusoperations/ 4 tests
    
    TestCompleteExternally/ 3 tests
    
    go.temporal.io/server/components/nexusoperations/TestCompleteExternally/backing_off-failed Inherited backing_off-failed
    
    go.temporal.io/server/components/nexusoperations/TestCompleteExternally/scheduled-failed Introduced here
    
    go.temporal.io/server/components/nexusoperations/TestCompleteExternally/started-failed Inherited started-failed
    
    TestCompleteFromAttempt/ 1 test
    
    go.temporal.io/server/components/nexusoperations/TestCompleteFromAttempt/failed Introduced here