TunnelViewModel: Don't call peer change handler if there are no changes

Signed-off-by: Roopesh Chander <roop@roopc.net>

WireGuard/WireGuard/UI/TunnelViewModel.swift

@@ -462,9 +462,11 @@ class TunnelViewModel {
                 }
             }
             scratchpad = otherScratchPad
+            if !changes.isEmpty {
                 changeHandler(peerIndex, changes)
             }
         }
+    }
 
     enum SaveResult<Configuration> {
         case saved(Configuration)