Remove scholarship validation from application model

[bencodeorg]

Education team noticed a bug where no updates (of any kind) could be made to CSP scholarships with the new EIR scholarship status.

Problem is a validation on the application that I missed, which validates the scholarship status. My approach here was to remove this validation -- I think it is redundant because:

• an application retrieves its scholarship status (or lack thereof) from the scholarshipInfo model,
• which has its own validation for whether the scholarship is in the list of possible scholarship options.

Testing story

[manual] After reproducing the original issue locally, I've tested that it no longer occurs on an existing CSP or CSD application. Also checked that I can create an application (via factory), and update the scholarship status via the application dashboard.

[automated, per Clare's suggestion] added test that failed prior to this change, and passes with it.

Reviewer Checklist:

• Tests provide adequate coverage
• Code is well-commented
• New features are translatable or updates will not break translations
• Relevant documentation has been added or updated
• User impact is well-understood and desirable
• Pull Request is labeled appropriately
• Follow-up work items (including potential tech debt) are tracked and linked

[molly-moen]

did you check if these constants are used incorrectly anywhere else?

[bencodeorg]

good thought -- I just went through and double checked that all uses of Pd::ScholarshipInfoConstants::something are of individual constants (not lists) that still exist (eg, Pd::ScholarshipInfoConstants::NO).

I think I may have confused myself the first time around when I used things like Pd::ScholarshipInfo::YES_CDO, which is possible because Pd::ScholarshipInfoConstants is included at the top of the Pd::ScholarshipInfo model. I've moved references to the more confusing use of constants to the less confusing version in my most recent commit.

[molly-moen]

LGTM