fix getProposal api error

Author: ellen-wright

apps/backend/src/resolvers/types/Questionary.ts

@@ -38,7 +38,7 @@ export class QuestionaryResolver {
     );
   }
 
-  @FieldResolver(() => Boolean)
+  @FieldResolver(() => Boolean, { nullable: true })
   async isCompleted(
     @Root() questionary: Questionary,
     @Ctx() context: ResolverContext

apps/backend/src/resolvers/types/QuestionaryStep.ts

@@ -10,7 +10,7 @@ export class QuestionaryStep implements Partial<QuestionaryStepOrigin> {
   public topic: Topic;
 
   @Field()
-  public isCompleted: boolean;
+  public isCompleted?: boolean;
 
   @Field(() => [Answer])
   public fields: Answer[];