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 94.85447% with 99 lines in your changes missing coverage. Please review.

Project coverage is 75.87599%. Comparing base (cac5a6c) to head (2434e29).
Report is 2 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #12489         +/-   ##
===================================================
+ Coverage   75.75486%   75.87599%   +0.12113%     
===================================================
  Files           3159        3163          +4     
  Lines         635942      637705       +1763     
  Branches       46987       47063         +76     
===================================================
+ Hits          481757      483865       +2108     
+ Misses        150726      150378        -348     
- Partials        3459        3462          +3     

Flag	Coverage Δ
Debug	75.87599% <94.85447%> (+0.12113%)	⬆️
integration	18.15263% <0.00000%> (-0.02605%)	⬇️
production	49.51107% <82.35294%> (+0.19386%)	⬆️
test	97.05725% <100.00000%> (+0.01133%)	⬆️
unit	46.73026% <82.35294%> (+0.19926%)	⬆️

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[paul1956]

@Tanya-Solyanik this PR should be DRAFT, please.