Fix issue#9807 2nd draft (Replaces PR #11867) DRAFT

[paul1956]

Fixes #9807

Proposed changes

• Add Remove dependance on WebClient for VB FileDownload by using HttpClient
• Upload still uses WebClient that also needs to be done as a separate PR

Customer Impact

• Adds Async file download support to VB, and if WebClient goes away this will allow existing Visual Basic programs using synchronous File Download to still work.
• It also enables Async FileDownload is API is approved

Regression?

• Yes, when WebClient if and when goes away, not today

Risk

• The existing code uses ICredentials in some of the paths, it is unclear how compatible that is between WebClient and HttpClient

• Close to 100% Code Coverage Before and After change, original tests had no tests and there Error Message handling was odd

• There are Exception Messages that need to move from WebClient to this PR and be translated.

Microsoft Reviewers: Open in CodeFlow

[codecov]

Codecov Report

Attention: Patch coverage is 95.63847% with 83 lines in your changes missing coverage. Please review.

Project coverage is 75.81990%. Comparing base (d5bd070) to head (ea1d00f).

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #12489         +/-   ##
===================================================
+ Coverage   75.73525%   75.81990%   +0.08465%     
===================================================
  Files           3153        3157          +4     
  Lines         635807      637549       +1742     
  Branches       46975       47049         +74     
===================================================
+ Hits          481530      483389       +1859     
+ Misses        150842      150725        -117     
  Partials        3435        3435                 

Flag	Coverage Δ
Debug	75.81990% <95.63847%> (+0.08465%)	⬆️
integration	18.15957% <0.00000%> (-0.11086%)	⬇️
production	49.41991% <84.62963%> (+0.10945%)	⬆️
test	97.06268% <100.00000%> (+0.01161%)	⬆️
unit	46.49943% <84.62963%> (+0.20922%)	⬆️

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