feat: multi tab by episode group in SubjectDetails.vue when episode count gt 20

[chivehao]

• [x] Update the CHANGES log.
• [x] If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes #.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 47.10%. Comparing base (4669a22) to head (8c9942b).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #655 +/- ## ========================================= Coverage 47.10% 47.10% Complexity 855 855 ========================================= Files 196 196 Lines 7460 7460 Branches 389 389 ========================================= Hits 3514 3514 Misses 3812 3812 Partials 134 134 ```

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