Removed the requried from base64 when getting any attachment

Marco.Pms.Model/Utilities/FileUploadModel.cs

@@ -4,7 +4,7 @@
     {
         public Guid? DocumentId { get; set; }
         public required string FileName { get; set; }          // Name of the file (e.g., "image1.png")
-        public required string Base64Data { get; set; }       // Base64-encoded string of the file
+        public string? Base64Data { get; set; }       // Base64-encoded string of the file
         public required string ContentType { get; set; }      // MIME type (e.g., "image/png", "application/pdf")
         public long FileSize { get; set; }           // File size in bytes
         public string? Description { get; set; }      // Optional: Description or purpose of the file