Update property accessor and resource management

Modified the `ByteData` property in `DocumentDto.cs` to use a `set` accessor instead of `init`, enabling updates after initialization.

Updated resource manager references in `frmEnvelopeMainData.vb` to use `CommonServices.My.Resources.Model.ResourceManager` for localized string retrieval.

EnvelopeGenerator.Application/Common/Dto/DocumentDto.cs

@@ -23,5 +23,5 @@ public record DocumentDto : DocumentDetailsDto
     /// <summary>
     /// Gets or sets the binary data of the document, if available.
     /// </summary>
-    public byte[]? ByteData { get; init; }
+    public byte[]? ByteData { get; set; }
 }