Refactored `DocumentService.GetDocumentAsync` to throw
`HttpRequestException` on failure instead of returning a tuple.
Updated all consumers to handle exceptions, improving error
handling consistency across the application.
Enhanced error messages for better user feedback and added
logging for improved traceability. Updated `EnvelopeReceiverPage`,
`EnvelopeReceiverPage_DxReportViewer`, and `ReportViewer` to
use the new exception-based API and handle errors gracefully.
This change simplifies the API, improves maintainability, and
makes the application more robust and user-friendly.
Introduced a new `DocumentService` class to handle fetching
PDF document bytes from an API endpoint. The service uses
`HttpClient` for HTTP communication and `IOptions<ApiOptions>`
for accessing API configuration. Added the `GetDocumentAsync`
method to perform the HTTP GET request, handle responses, and
return the document bytes along with the HTTP status code.
Included necessary `using` directives and encapsulated the
service in the `EnvelopeGenerator.ReceiverUI.Services` namespace.
