chore(ci): generate junit xml files

[JP-Ellis]

📝 Summary

Generate junit XML files to be parsed by CodeCov

🚨 Breaking Changes

🔥 Motivation

🔨 Test Plan

🔗 Related issues/PRs

[Copilot]

Pull Request Overview

This PR adds JUnit XML file generation to the test workflow for CodeCov integration. The changes enable test results to be parsed and uploaded to CodeCov for better test reporting and analysis.

• Adds --junit-xml flags to all test commands to generate XML test result files
• Introduces a new CodeCov test results upload step that runs regardless of test outcome
• Updates both main test jobs and example test jobs to generate JUnit XML output

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (main@f11facd). Learn more about missing BASE report.
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@          Coverage Diff           @@
##             main   #1247   +/-   ##
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  Coverage        ?     52%           
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  Files           ?      32           
  Lines           ?    3725           
  Branches        ?       0           
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  Hits            ?    1963           
  Misses          ?    1762           
  Partials        ?       0           

Flag	Coverage Δ
tests	52% <ø> (?)

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