add a reset core data option in manage account menu

apple/OmnivoreKit/Sources/App/Views/Profile/ManageAccountView.swift

@@ -37,6 +37,12 @@ struct ManageAccountView: View {
           },
           label: { Text("Delete Account") }
         )
+        Button(
+          action: {
+            dataService.resetCoreData()
+          },
+          label: { Text("Reset Data Cache") }
+        )
         .alert(isPresented: $showDeleteAccountConfirmation) {
           Alert(
             title: Text("Are you sure you want to delete your account? This action can't be undone."),

apple/OmnivoreKit/Sources/Services/DataService/DataService.swift

@@ -95,7 +95,7 @@ public final class DataService: ObservableObject {
     }
   }
 
-  func resetCoreData() {
+  public func resetCoreData() {
     UserDefaults.standard.set(
       DateFormatter.formatterISO8601.string(from: Date(timeIntervalSinceReferenceDate: 0)),
       forKey: UserDefaultKey.lastItemSyncTime.rawValue