fix: Fixed function pertaining to previous month's ticket sales

[mrsaicharan1]

Fixes #6333

Short description of what this resolves:

Follow up on #6287

Changes proposed in this pull request:

• Used ticket_sales_object

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.
• The unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

• All the functions created/modified in this PR contain relevant docstrings.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (development@257b354). Click here to learn what that means.
The diff coverage is 0%.

@@              Coverage Diff               @@
##             development    #6334   +/-   ##
==============================================
  Coverage               ?   65.28%           
==============================================
  Files                  ?      287           
  Lines                  ?    14727           
  Branches               ?        0           
==============================================
  Hits                   ?     9614           
  Misses                 ?     5113           
  Partials               ?        0

Impacted Files	Coverage Δ
app/models/event.py	78.49% <0%> (ø)

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