Use Club.get_officer_emails() to send alerts

[aviupadhyayula]

Replaces duplicated logic across notification flows.

[sentry-io]

🔍 Existing Issues For Review

Your pull request is modifying functions with the following pre-existing issues:

📄 File: backend/clubs/models.py

Function	Unhandled Issue
__str__	AttributeError: 'NoneType' object has no attribute 'name' /api/admin/clubs/applicationsu... Event Count: 4

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[codecov]

Codecov Report

Attention: Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 71.39%. Comparing base (fbedec8) to head (9fb6eb8).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
backend/clubs/models.py	40.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #729      +/-   ##
==========================================
- Coverage   71.40%   71.39%   -0.02%     
==========================================
  Files          31       31              
  Lines        6850     6851       +1     
==========================================
  Hits         4891     4891              
- Misses       1959     1960       +1     

Flag	Coverage Δ
	71.39% <40.00%> (-0.02%)	⬇️

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