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/Pages/EnvelopeReceiverPage_DxReportViewer.razor

@@ -23,7 +23,7 @@
     byte[]? _basePdfBytes;
 
     protected override async Task OnInitializedAsync() {
-        if (!AppOptions.Value.ForceToUseFakeDocument) {
+        if (!AppOptions.Value.UsePredefinedReports) {
             var (pdfBytes, _) = await DocumentService.GetDocumentAsync(EnvelopeKey);
             if (pdfBytes is { Length: > 0 })
                 _basePdfBytes = pdfBytes;