GetWorkflowStateAsync should always return WorkflowState

[WhitWaldo]

Description

Ensuring that GetWorkflowStateAsync always returns a WorkflowState so the WorkflowState.Exists properly reflects the presence of the value (or not). This was erroneously returning null if the metadata wasn't available when this is, in fact, a supported value in the WorkflowState object, so I'm applying this fix. The signature doesn't change, just the behavior, so this shouldn't be a dramatic breaking change.

Thank you to @atrauzzi for the helpful discussion in which this was pointed out.

Also, after a very long discussion with @atrauzzi about the merits of logging at the SDK level, he's won me over and I'm also removing the error that was previously logged when using GetWorkflowStateAsync when the workflow was returned as not existing. He's right in his assertion that an error was too severe for an operation that completed successfully. The error remains if the runtime returns an unexpected value (null or some other response shape), but will no longer log if it's just a matter of a workflow instance not existing in the runtime.

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #[issue number]

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.18%. Comparing base (027c724) to head (7ed6707).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1847      +/-   ##
==========================================
- Coverage   63.19%   63.18%   -0.02%     
==========================================
  Files         330      330              
  Lines        9534     9534              
  Branches     1110     1110              
==========================================
- Hits         6025     6024       -1     
  Misses       3198     3198              
- Partials      311      312       +1     

Flag	Coverage Δ
net10.0	63.14% <ø> (-0.02%)	⬇️

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[atrauzzi]

Love it! As always @WhitWaldo, thank you for your vigilance as the keeper of the Dapr dotnet scrolls! ✊

[atrauzzi]

😍

[WhitWaldo]

@barakbbn If there are other issues like this you're experiencing, please don't hesitate to file an issue about it so I can address them too!

[atrauzzi]

@barakbbn -- Echoing what Whit said: We would absolutely love to have you (or anyone reading this) open tickets about any pain points or inconsistencies you think exist in the SDK! 🙏