Merged PR 1058: File Lengthのソートが正しく行われない_Funtion側修正漏れの修正

Funtion側もデータ型の変更に合わせる修正をいたしました。

動作確認状況
```
Test Suites: 8 passed, 8 total
Tests:       46 passed, 46 total
Snapshots:   0 total
Time:        85.851 s
Ran all test suites.
```

dictation_function/src/entity/audio_file.entity.ts

@@ -22,7 +22,7 @@ export class AudioFile {
   @Column()
   started_at: Date;
   @Column({ type: "time" })
-  duration: string;
+  duration: number;
   @Column()
   finished_at: Date;
   @Column()

dictation_function/src/test/common/utility.ts

@@ -564,7 +564,7 @@ export const makeTestTask = async (
       author_id: "test_author",
       work_type_id: "test_work_type",
       started_at: new Date(),
-      duration: "00:00:00",
+      duration: 0,
       finished_at: new Date(),
       uploaded_at: new Date(),
       file_size: 1024,

dictation_function/src/test/deleteAudioFiles.spec.ts

@@ -1282,7 +1282,7 @@ describe("deleteRecords | 削除対象タスク等を削除できる", () => {
           author_id: "test_author",
           work_type_id: "test_work_type",
           started_at: new Date(),
-          duration: "00:00:00",
+          duration: 0,
           finished_at: new Date(),
           uploaded_at: new Date(),
           file_size: 1024,