fix(backend): 存在しないActorに対するDeleteアクティビティは無視するように

[kakkokari-gtyih]

What

Why

Fix #17293

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 14.92%. Comparing base (92e0e8e) to head (908daba).
⚠️ Report is 5 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff              @@
##           develop   #17294       +/-   ##
============================================
- Coverage    63.79%   14.92%   -48.88%     
============================================
  Files         1162      242      -920     
  Lines       116401    11864   -104537     
  Branches      8455     4014     -4441     
============================================
- Hits         74261     1771    -72490     
+ Misses       39941     7930    -32011     
+ Partials      2199     2163       -36     

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[github-actions]

このPRによるapi.jsonの差分
差分はありません。
Get diff files from Workflow Page

[github-actions]

Backend memory usage comparison

Before GC

Metric	base (MB)	head (MB)	Diff (MB)	Diff (%)
VmRSS	316.13 MB	320.09 MB	+3.95 MB	+1.25%
VmHWM	316.13 MB	320.09 MB	+3.95 MB	+1.25%
VmSize	23109.35 MB	23115.68 MB	+6.33 MB	+0.02%
VmData	1380.21 MB	1386.18 MB	+5.96 MB	+0.43%

After GC

Metric	base (MB)	head (MB)	Diff (MB)	Diff (%)
VmRSS	316.13 MB	320.09 MB	+3.95 MB	+1.25%
VmHWM	316.13 MB	320.09 MB	+3.95 MB	+1.25%
VmSize	23109.35 MB	23115.68 MB	+6.33 MB	+0.02%
VmData	1380.21 MB	1386.18 MB	+5.96 MB	+0.43%

After Request

Metric	base (MB)	head (MB)	Diff (MB)	Diff (%)
VmRSS	316.46 MB	320.49 MB	+4.02 MB	+1.27%
VmHWM	316.46 MB	320.49 MB	+4.02 MB	+1.27%
VmSize	23109.35 MB	23115.68 MB	+6.33 MB	+0.02%
VmData	1380.21 MB	1386.18 MB	+5.96 MB	+0.43%

See workflow logs for details

[syuilo]

🙏