[WB-8176] Use Artifacts when put into run config. Accept a string to represent an artifact in the run config

[KyleGoyette]

Fixes WB-8176

Description

What does the PR do?

Design doc

Testing

How was this PR tested?

Checklist

• Name PR "[WB-NNNN][WB-MMMM] Add support for..." similar to entries in CHANGELOG.md
• Include reference to internal ticket "Fixes WB-NNNN" (and github issue "Fixes #NNNN" if applicable)

[codecov]

Codecov Report

Merging #3203 (9aff640) into master (e64c0e2) will increase coverage by 0.05%.
The diff coverage is 93.65%.

@@            Coverage Diff             @@
##           master    #3203      +/-   ##
==========================================
+ Coverage   79.99%   80.04%   +0.05%     
==========================================
  Files         213      213              
  Lines       28039    28089      +50     
==========================================
+ Hits        22430    22485      +55     
+ Misses       5609     5604       -5     

Flag	Coverage Δ
functest	56.62% <36.50%> (-0.02%)	⬇️
unittest	69.48% <93.65%> (+0.04%)	⬆️

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

Impacted Files	Coverage Δ
wandb/util.py	85.69% <90.00%> (+0.10%)	⬆️
wandb/sdk/wandb_run.py	88.69% <93.33%> (+0.22%)	⬆️
wandb/sdk/wandb_config.py	94.96% <100.00%> (+0.18%)	⬆️
wandb/sdk/wandb_init.py	85.17% <100.00%> (+0.15%)	⬆️
wandb/sdk/wandb_artifacts.py	81.57% <0.00%> (-0.11%)	⬇️
wandb/sdk/lib/git.py	76.35% <0.00%> (ø)
wandb/sdk/lib/sock_client.py	94.73% <0.00%> (+1.75%)	⬆️
wandb/sdk/internal/meta.py	90.74% <0.00%> (+3.08%)	⬆️

[stephchen]

the logic in use_artifact is getting kinda convoluted and hard to follow but otherwise looks fine to me