Remove Use of VisualStudioCredential

[brianrob]

Addresses failures where the VisualStudioCredential requires re-authentication. This gets hidden in in the exception text in the log and isn't presented to the user. Instead, we'll go ahead and interactively prompt the user once per session.

SymwebAuth: [Exception getting token. Azure.Identity.AuthenticationFailedException: The ChainedTokenCredential failed due to an unhandled exception: VisualStudioCredential authentication failed: One or more errors occurred. ---> Azure.Identity.AuthenticationFailedException: VisualStudioCredential authentication failed: One or more errors occurred. ---> System.AggregateException: One or more errors occurred. ---> Azure.Identity.AuthenticationFailedException: Process "D:\VisualStudio\Dev18\main\Enterprise\Common7\IDE\CommonExtensions\Microsoft\Asal\TokenService\Microsoft.Asal.TokenService.exe" has failed with unexpected error: TS003: Error, TS001: This account '<redacted>' needs re-authentication. Please open Visual Studio, go to Tools->Options->Azure Services Authentication, and re-authenticate the account you want to use.. ---> System.InvalidOperationException: TS003: Error, TS001: This account '<redacted>' needs re-authentication. Please open Visual Studio, go to Tools->Options->Azure Services Authentication, and re-authenticate the account you want to use.
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Azure.Identity.VisualStudioCredential.<RunProcessesAsync>d__29.MoveNext()
   --- End of inner exception stack trace ---
   --- End of inner exception stack trace ---
   at Azure.Identity.VisualStudioCredential.<RunProcessesAsync>d__29.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Identity.VisualStudioCredential.<GetTokenImplAsync>d__27.MoveNext()
   --- End of inner exception stack trace ---
   at Azure.Identity.CredentialDiagnosticScope.FailWrapAndThrow(Exception ex, String additionalMessage, Boolean isCredentialUnavailable)
   at Azure.Identity.VisualStudioCredential.<GetTokenImplAsync>d__27.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Identity.VisualStudioCredential.<GetTokenAsync>d__25.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Azure.Identity.ChainedTokenCredential.<GetTokenImplAsync>d__7.MoveNext()
   --- End of inner exception stack trace ---
   at Azure.Identity.ChainedTokenCredential.<GetTokenImplAsync>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Identity.ChainedTokenCredential.<GetTokenAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Diagnostics.Symbols.Authentication.SymwebHandler.<GetTokenAsync>d__8.MoveNext()]

[brianrob]

Closing in favor of #2278.