Ensure we raise if onboarding was to fail for any reason

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: danhalson

lib/concepts/school/operations/create.rb

@@ -11,7 +11,10 @@ def call(school_params:, creator_id:, token:)
           response[:school].save!
 
           # TODO: Remove this conditional once the feature flag is retired
-          SchoolOnboardingService.new(response[:school]).onboard(token:) if FeatureFlags.immediate_school_onboarding?
+          if FeatureFlags.immediate_school_onboarding?
+            onboarded = SchoolOnboardingService.new(response[:school]).onboard(token:)
+            raise "School onboarding failed" unless onboarded
+          end
         end
 
         response