fix(storybook): use type-only imports in generated stories

[zyoshoka]

What

verbatimModuleSyntax を有効化して以降 Storybook が動かなくなっているのを修正します。Story の生成ロジックを修正して型のみのインポートを行います。

Why

Follow-up to #15323

Additional info (optional)

Checklist

• Read the contribution guide
• Test working in a local environment
• (If needed) Add story of storybook
• (If needed) Update CHANGELOG.md
• (If possible) Add tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 15.29%. Comparing base (8508c4d) to head (23694a4).
Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff              @@
##           develop   #15654       +/-   ##
============================================
- Coverage    41.84%   15.29%   -26.56%     
============================================
  Files         1626      788      -838     
  Lines       166236    72549    -93687     
  Branches      4124     1280     -2844     
============================================
- Hits         69568    11095    -58473     
+ Misses       96189    61028    -35161     
+ Partials       479      426       -53     

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[syuilo]

🙏