Fix: Make m230401_174208_add_allow_jwt_auth migration resilient when module is not bootstrapped

[luke-]

Summary

• Replace Yii::$app->getModule('rest')->settings calls with direct setting table queries — the module may not be registered during migrate/up (core #[WithoutModuleAutoload] skips third-party module bootstrap)
• Use upsert() for writing settings, making the migration naturally idempotent

Test plan

• Run migrate/up on an instance where rest was previously installed — migration should complete without errors
• Run migrate/up a second time — upsert makes it idempotent, should skip cleanly
• Verify enableJwtAuth is set correctly based on whether jwtKey was previously configured