bugfix(workflows): Addressing "no such instance exists" errors

[WhitWaldo]

Description

The ProcessActivityAsync method had a single try/catch method that wrapped both the handler execution and gRPC delivery calls. When an activity completed successfully, but CompleteActivityTaskAsync threw (transiently), the trigger here being no such instance exists from the sidecar, the RpcException was caught by the outer handler which treated it as an activity failure and made a second CompleteActivityTaskAsync call with the error message from that exception. The sidecar accepted this second call and recorded a TaskFailed history event, so on the next replay, HandleFailedActivityFromHistory found this event and threw a WorkflowTaskFailedException with the unknown status code and this detail propagating a transient transport error as a permanent business-logic failure.

This simply splits the single try/catch block into two separate blocks:

• The first addresses the handler execution
• The second covers only the deliver call

This means no second Complete*Async call is ever made when delivery fails and no spurious TaskFailed events are written to history.

Added unit tests to validate.

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 65.42%. Comparing base (3516729) to head (9b9c1bd).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1812   +/-   ##
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  Coverage   65.42%   65.42%           
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  Files         296      296           
  Lines        8694     8694           
  Branches     1009     1009           
=======================================
  Hits         5688     5688           
  Misses       2761     2761           
  Partials      245      245           

Flag	Coverage Δ
net10.0	65.41% <ø> (ø)

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