Remove deprecated track_struct_event

[mikealfare]

Problem

snowplow_tracking is deprecating track_struct_event.

Solution

Per the suggestion in the deprecation warning, use StructuredEvent instead.

Checklist

• I have read the contributing guide and understand what's expected of me.
• I have run this code in development, and it appears to resolve the stated issue.
• This PR includes tests, or tests are not required or relevant for this PR.
• This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• This PR includes type annotations for new and modified functions.

[github-actions]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the contributing guide.

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 88.95%. Comparing base (054c6fd) to head (ea4f0ef).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10736   +/-   ##
=======================================
  Coverage   88.95%   88.95%           
=======================================
  Files         181      181           
  Lines       22959    22960    +1     
=======================================
+ Hits        20424    20425    +1     
  Misses       2535     2535           

Flag	Coverage Δ
integration	86.14% <66.66%> (+<0.01%)	⬆️
unit	62.37% <66.66%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
Unit Tests	62.37% <66.66%> (+<0.01%)	⬆️
Integration Tests	86.14% <66.66%> (+<0.01%)	⬆️