fix(backend): update ApPersonService to handle user without endpoint

[PichuChen]

What

Fix #13735

Why

endpoint または sharedInbox がnullの場合、更新をスキップします

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

[github-actions]

このPRによるapi.jsonの差分

差分はこちら

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 65.27%. Comparing base (a6edd50) to head (95b5c47).

Files	Patch %	Lines
...end/src/core/activitypub/models/ApPersonService.ts	0.00%	6 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #14080      +/-   ##
===========================================
+ Coverage    61.94%   65.27%   +3.33%     
===========================================
  Files         1004     1004              
  Lines       115259   115261       +2     
  Branches      4594     4570      -24     
===========================================
+ Hits         71399    75241    +3842     
+ Misses       43828    39993    -3835     
+ Partials        32       27       -5     

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