Refactor: Replace ForceToUseFakeDocument property

Replaced the `ForceToUseFakeDocument` property in `ApiOptions`
with `UsePredefinedReports` to improve clarity and better align
with business requirements. Updated all references in
`EnvelopeReceiverPage_DxReportViewer.razor` and
`ReportViewer.razor` to use the new property, ensuring
consistency and maintaining functionality.

EnvelopeGenerator.ReceiverUI/Options/ApiOptions.cs

@@ -6,5 +6,5 @@ public class ApiOptions
 
     public string BaseUrl { get; set; } = string.Empty;
 
-    public bool ForceToUseFakeDocument { get; set; } = false;
+    public bool UsePredefinedReports { get; set; } = false;
 }