Intent of only_user_SAs_—_all_preserved

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
  - chasm/ 2 tests
    
    lib/ 2 tests
    
    scheduler/ 2 tests
    
    migration/ 2 tests
    
    TestLegacyToCreateFromMigrationStateRequest_StripsSystemSearchAttributes/ 2 tests
    
    go.temporal.io/server/chasm/lib/scheduler/migration/TestLegacyToCreateFromMigrationStateRequest_StripsSystemSearchAttributes/only_user_SAs_—_all_preserved Introduced here
    
    go.temporal.io/server/chasm/lib/scheduler/migration/TestLegacyToCreateFromMigrationStateRequest_StripsSystemSearchAttributes/user_SA_preserved,_system_SAs_stripped Inherited user_SA_preserved,_system_SAs_stripped