Fixed ref-num being double-generated

Author: jbarnsley10

src/server/plugins/engine/pageControllers/StatusPageController.ts

@@ -58,7 +58,7 @@ export class StatusPageController extends QuestionPageController {
         submissionGuidance,
         formName,
         showReferenceNumber: this.showReferenceNumber,
-        referenceNumber: context.referenceNumber
+        referenceNumber: confirmationState.referenceNumber
       })
     }
   }

src/server/plugins/engine/pageControllers/SummaryPageController.ts

@@ -174,7 +174,8 @@ export class SummaryPageController extends QuestionPageController {
 
     await cacheService.setConfirmationState(request, {
       confirmed: true,
-      formId: context.state.formId
+      formId: context.state.formId,
+      referenceNumber: context.referenceNumber
     } as FormConfirmationState)
 
     // Clear all form data

src/server/plugins/engine/types.ts

@@ -100,6 +100,7 @@ export interface FormSubmissionError
 export interface FormConfirmationState {
   confirmed?: true
   formId?: string
+  referenceNumber?: string
 }
 
 export interface FormPayloadParams {