Fix issue#9807 review 2nd (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

❌ Patch coverage is 94.72387% with 214 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.35303%. Comparing base (6d20991) to head (349f3e2).
⚠️ Report is 146 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #12489         +/-   ##
===================================================
+ Coverage   77.15155%   77.35303%   +0.20148%     
===================================================
  Files           3278        3288         +10     
  Lines         645199      649005       +3806     
  Branches       47716       48022        +306     
===================================================
+ Hits          497781      502025       +4244     
+ Misses        143724      143285        -439     
- Partials        3694        3695          +1     

Flag	Coverage Δ
Debug	77.35303% <94.72387%> (+0.20148%)	⬆️
integration	18.95881% <0.00000%> (-0.03084%)	⬇️
production	52.29200% <83.08458%> (+0.27161%)	⬆️
test	97.40889% <97.60148%> (+0.00225%)	⬆️
unit	49.72600% <83.08458%> (+0.26238%)	⬆️

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[paul1956]

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