Auto-correct some Rails Rubocop violations

[Hamms]

Specifically, run:

bundle exec rubocop --auto-correct --only Rails/FindById,Rails/IndexBy,Rails/RedundantForeignKey,Rails/WhereNot

Followed by:

bundle exec rubocop --auto-correct-all --only Rails/ActiveRecordAliases,Rails/ApplicationRecord,Rails/SafeNavigationWithBlank

The result of this is that the following desired rules are re-enabled:

• Rails/ActiveRecordAliases
• Rails/ApplicationRecord
• Rails/FindById
• Rails/IndexBy
• Rails/SafeNavigationWithBlank
• Rails/RedundantForeignKey
• Rails/WhereNot

We also incidentally re-enable the Lint/Debugger rule. Not sure why this one was disabled in the first place, but I'm glad to see it gone!

PR Checklist:

• Tests provide adequate coverage
• Privacy and Security impacts have been assessed
• 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