Emit ArtifactWritten event when artifacts are written

[QMalcolm]

Resolves #10937

Problem

We recently ran into an issue where the run_results.json artifact wasn't being written (#10934). One of the struggles when debugging was whether core was even trying to write out the artifact.

Solution

Emit an ArtifactWritten event whenever an artifact is written

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.

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 5 lines in your changes missing coverage. Please review.

Project coverage is 89.16%. Comparing base (dd77210) to head (b4d753d).
Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10940      +/-   ##
==========================================
- Coverage   89.19%   89.16%   -0.04%     
==========================================
  Files         183      183              
  Lines       23496    23517      +21     
==========================================
+ Hits        20958    20968      +10     
- Misses       2538     2549      +11     

Flag	Coverage Δ
integration	86.54% <75.00%> (-0.05%)	⬇️
unit	62.05% <40.00%> (-0.03%)	⬇️

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

Components	Coverage Δ
Unit Tests	62.05% <40.00%> (-0.03%)	⬇️
Integration Tests	86.54% <75.00%> (-0.05%)	⬇️