Add presence validation for enic_reason

[gms-gs]

Context

Enforce presence validation for enic_reason on ApplicationQualifications ONLY on create

Changes proposed in this pull request

Add validates :enic_reason, presence: true, on: :create to the ApplicationQualification model

Things to check

• If the code removes any existing feature flags, a data migration has also been added to delete the entry from the database
• This code does not rely on migrations in the same Pull Request
• If this code includes a migration adding or changing columns, it also backfills existing records for consistency
• If this code adds a column to the DB, decide whether it needs to be in analytics yml file or analytics blocklist
• API release notes have been updated if necessary
• If it adds a significant user-facing change, is it documented in the CHANGELOG?
• Required environment variables have been updated added to the Azure KeyVault
• Inform data insights team due to database changes

[dcyoung-dev]

How do you feel about adding specs for the endpoints that caused the Sentry errors?

[gms-gs]

How do you feel about adding specs for the endpoints that caused the Sentry errors?

I very feel! Yeahh Ill add that in

[dcyoung-dev]

I think the tests aren't adding much value as they create Qualifications with an enic_reason we want to solve the issue of existing Qualifications that don't have an enic_reason first before we backfill. If we backfill first we run the risk of still having nils

[gms-gs]

This test is just so we can be sure that when a user updates an existing qualification before the backfill PR, that we don't get enic_reason validation error. But we still want to validate the presence of an enic_reason on creation of any new qualifications. Reason for testing here is when we added the validation before it caused a validation error when updating a qualification. But as we now only validate on create this is expected test behaviour where it keeps the enic_reason as nil for an existing qualification