feat: remove deprecated exam fields (#62852)

client/src/templates/Challenges/exam-download/attempts.tsx

@@ -59,8 +59,8 @@ export function Attempts({ id }: AttemptsProps) {
       </thead>
       <tbody>
         {attempts.map(attempt => (
-          <tr key={attempt.startTimeInMS}>
-            <td>{new Date(attempt.startTimeInMS).toTimeString()}</td>
+          <tr key={attempt.startTime}>
+            <td>{new Date(attempt.startTime).toTimeString()}</td>
             <td>
               {attempt.result
                 ? `${attempt.result.percent}%`

client/src/utils/ajax.ts

@@ -223,7 +223,8 @@ export interface Exam {
 export interface Attempt {
   id: string;
   examId: string;
-  startTimeInMS: number;
+  // ISO 8601 string
+  startTime: string;
   questionSets: unknown[];
   result?: {
     passed: boolean;