Fix crash if draft attachment lacks data

Packages/ComposeUI/Sources/ComposeUI/Controllers/AttachmentThumbnailController.swift

@@ -112,6 +112,9 @@ class AttachmentThumbnailController: ViewController {
 //                    }
                 }
             }
+            
+        case .none:
+            break
         }
     }
     

Packages/ComposeUI/Sources/ComposeUI/CoreData/DraftAttachment.swift

@@ -58,7 +58,7 @@ public final class DraftAttachment: NSManagedObject, Identifiable {
         } else if let fileURL, let fileType {
             return .file(fileURL, UTType(fileType)!)
         } else {
-            fatalError()
+            return .none
         }
     }
     
@@ -76,6 +76,7 @@ public final class DraftAttachment: NSManagedObject, Identifiable {
         case drawing(PKDrawing)
         case file(URL, UTType)
         case editing(String, Attachment.Kind, URL)
+        case none
     }
     
     public override func prepareForDeletion() {
@@ -246,6 +247,8 @@ extension DraftAttachment {
                     completion(.success((fileData, type)))
                 }
             }
+        } else {
+            completion(.failure(.noData))
         }
     }
     
@@ -309,5 +312,6 @@ extension DraftAttachment {
         case noVideoExportSession
         case loadingDrawing
         case loadingData
+        case noData
     }
 }