fix: Filter attendees when ticket holder is not ticket purchaser

[codedsun]

Fixes #7397

Short description of what this resolves:

feat: Filter attendees when ticket holder is not ticket purchaser

Changes proposed in this pull request:

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

Merging #7471 (9098e01) into development (280ac5b) will decrease coverage by 0.02%.
The diff coverage is 25.00%.

@@               Coverage Diff               @@
##           development    #7471      +/-   ##
===============================================
- Coverage        65.41%   65.38%   -0.03%     
===============================================
  Files              265      265              
  Lines            13244    13252       +8     
===============================================
+ Hits              8663     8665       +2     
- Misses            4581     4587       +6     

Impacted Files	Coverage Δ
app/api/attendees.py	55.64% <0.00%> (-0.92%)	⬇️
app/api/schema/orders.py	96.82% <ø> (ø)
app/models/order.py	84.78% <33.33%> (-3.59%)	⬇️

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