Fix Run valve isolation trace.

Author: CalebRas

Shared/Samples/Run valve isolation trace/RunValveIsolationTraceView.Model.swift

@@ -148,7 +148,7 @@ extension RunValveIsolationTraceView {
 
                 addGraphic(for: point, traceLocationType: "starting point")
                 startingLocationPoint = point
-                tracingActivity = .none
+                tracingActivity = nil
 
                 // Get available utility categories.
                 if let definition = utilityNetwork.definition {
@@ -224,9 +224,10 @@ extension RunValveIsolationTraceView {
             } catch {
                 statusText = "Trace failed."
                 traceEnabled = true
+                tracingActivity = nil
                 return
             }
-            tracingActivity = .none
+            tracingActivity = nil
             traceEnabled = true
             resetEnabled = true
         }

Shared/Samples/Run valve isolation trace/RunValveIsolationTraceView.swift

@@ -82,7 +82,7 @@ struct RunValveIsolationTraceView: View {
                             Task { await mapViewProxy.setViewpointCenter(point, scale: 3_000) }
                         }
                     }
-                    .disabled(!model.resetEnabled)
+                    .disabled(!model.resetEnabled || model.tracingActivity == .runningTrace)
                 }
             }
             .sheet(isPresented: $isConfigurationPresented) {