Fix status in orphan feature

~~No PT/Jira story~~ JIRA story https://osraav.atlassian.net/browse/OSRA-160

- fix incorrect references to OrphanStatus/OrphanSponsorshipStatus in orphan.feature
- remove references to 'Sponsored'/'Unsponsored' as these belong to OrphanSponsorshipStatus and are never set manually
- add tests for fields in index view

## JIRA
OSRA-160 #Code-Review
I actually created something similar in the current PR I'm working on. I have a `Given all provinces and orphan statuses have been seeded` step as I depend on these to create orphans through the Excel importer. So, if this is something that is required in several places, I think it would be a good idea to have it as @NikitaAvvakumov described.