refactor: remove 'amount' argument from Quiz schema and update quiz retrieval logic

- Removed the 'amount' argument from the quiz retrieval query to streamline the schema.
- Updated the quiz retrieval logic to use 'nrOfQuestions' from the quiz object instead of the removed 'amount' argument, ensuring consistent behavior in quiz selection.
- Improved code clarity by refining comments related to quiz selection logic.

src/Quiz/quiz.schema.ts

@@ -155,10 +155,6 @@ export class QuizSchema extends PothosSchema {
             type: 'String',
             required: false,
           }),
-          amount: t.arg({
-            type: 'Int',
-            required: false,
-          }),
         },
         resolve: async (query, _root, args, ctx, _info) => {
           if (ctx.isSubscription) {
@@ -186,9 +182,9 @@ export class QuizSchema extends PothosSchema {
                 centerMentorId: centerMentor.mentorId,
               },
             })
-            // get amount of quizzes using args.amount and random index based on random
+            // get amount of quizzes using nrOfQuestions and random index based on random
             const randomIndex = Math.floor(random * quizzes.length)
-            return quizzes.slice(randomIndex, randomIndex + (args.amount ?? 1))
+            return quizzes.slice(randomIndex, randomIndex + (quizzes[0].nrOfQuestions ?? 1))
           }
 
           // use case 2: Customer