Intent of basic:_enable_from_nil_config

All 5 exact tests in this concept. Every test is marked by where it enters the hierarchy.

go.temporal.io/ 5 tests
- server/ 5 tests
  - service/ 5 tests
    
    history/ 5 tests
    
    api/ 5 tests
    
    updateworkflowoptions/ 5 tests
    
    TestMergeAndApply/ 5 tests
    
    go.temporal.io/server/service/history/api/updateworkflowoptions/TestMergeAndApply/basic:_disable_from_enabled_config Inherited basic:_disable_from_enabled_config
    
    go.temporal.io/server/service/history/api/updateworkflowoptions/TestMergeAndApply/basic:_enable_from_nil_config Introduced here
    
    go.temporal.io/server/service/history/api/updateworkflowoptions/TestMergeAndApply/basic:_fast-forward_from_nil Inherited basic:_fast-forward_from_nil
    
    go.temporal.io/server/service/history/api/updateworkflowoptions/TestMergeAndApply/nil_allowed:_nil_with_mask_clears_the_TSC Inherited nil_allowed:_nil_with_mask_clears_the_TSC
    
    go.temporal.io/server/service/history/api/updateworkflowoptions/TestMergeAndApply/reapply:_TSC_updated_with_same_fast-forward Inherited reapply:_TSC_updated_with_same_fast-forward