TenantId_Kind constructor Null safety

1. spine_client
2. tenant_id.pb
3. TenantId_Kind
4. TenantId_Kind const constructor

TenantId_Kind enum

1. Constructors
2. TenantId_Kind
3. Values
4. domain
5. email
6. value
7. notSet
8. Properties
9. hashCode
10. index
11. runtimeType
12. Methods
13. noSuchMethod
14. toString
15. Operators
16. operator ==
17. Constants
18. values