chore: Correct typo in event end mail

[ram-nad]

Fixes #5985

Checklist

• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream development branch.

Short description of what this resolves:

Changed the typing error in mail being sent after event ends.

[codecov]

Codecov Report

Merging #5990 into development will decrease coverage by 0.18%.
The diff coverage is n/a.

@@               Coverage Diff               @@
##           development    #5990      +/-   ##
===============================================
- Coverage        66.35%   66.17%   -0.19%     
===============================================
  Files              285      285              
  Lines            13941    14007      +66     
===============================================
+ Hits              9251     9269      +18     
- Misses            4690     4738      +48

Impacted Files	Coverage Δ
app/api/helpers/system_mails.py	100% <ø> (ø)	⬆️
app/api/users.py	30.53% <0%> (-1.35%)	⬇️

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[uds5501]

please change the PR title to fix: Correcting typo Issue otherwise its good to go

[ram-nad]

Changed the PR title and updated this branch.