feat: Add helper func in event DTOs

[cloudxxx8]

close #972

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• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
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Codecov Report

Attention: Patch coverage is 0% with 16 lines in your changes missing coverage. Please review.

Project coverage is 43.07%. Comparing base (c739c72) to head (cb0405d).

Files with missing lines	Patch %	Lines
dtos/requests/event.go	0.00%	8 Missing ⚠️
dtos/responses/event.go	0.00%	8 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #973      +/-   ##
==========================================
- Coverage   43.08%   43.07%   -0.02%     
==========================================
  Files         117      117              
  Lines        7151     7153       +2     
==========================================
  Hits         3081     3081              
- Misses       3727     3729       +2     
  Partials      343      343              

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[jinlinGuan]

LGTM