Show custom delegate for in-room user verification

This is independent of the in-room verification actually working, but prevents a fallback from appearing

src/timeline/MessageComponentChooser.qml

@@ -213,6 +213,14 @@ DelegateChooser {
         }
     }
 
+    DelegateChoice {
+        roleValue: MessageComponentType.Verification
+        delegate: MimeComponent {
+            mimeIconSource: "security-high"
+            label: i18n("%1 started a user verification", model.author.escapedDisplayName)
+        }
+    }
+
     DelegateChoice {
         roleValue: MessageComponentType.Other
         delegate: Item {}