Fix a minor bug that upload_artifact api does not return the latest artifacts.

[c-bata]

Contributor License Agreement

This repository (optuna-dashboard) and Goptuna share common code.
This pull request may therefore be ported to Goptuna.
Make sure that you understand the consequences concerning licenses and check the box below if you accept the term before creating this pull request.

• I agree this patch may be ported to Goptuna by other Goptuna contributors.

Reference Issues/PRs

None

What does this implement/fix? Explain your changes.

Fix a minor bug that upload_artifact api does not return the latest artifacts.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (bf7c930) 63.77% compared to head (265dfb4) 65.20%.
Report is 26 commits behind head on main.

Files	Patch %	Lines
optuna_dashboard/artifact/_backend.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #713      +/-   ##
==========================================
+ Coverage   63.77%   65.20%   +1.43%     
==========================================
  Files          35       35              
  Lines        2280     2285       +5     
==========================================
+ Hits         1454     1490      +36     
+ Misses        826      795      -31     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.