7541 Save plugin selection on onboarding complete

Previously, the plugin selection a user made was only stored if the next onboarding state was `.complete`.

Our original intention was to only save their selection when they reached `.complete`, so that if they returned to an unfinished onboarding flow they would start from the beginning, including the plugin selection.

This change fixes the bug that we wouldn’t save if they saw another onboarding step before `.complete`, by deferring the save until `.complete` rather than only checking the very next state.

Author: joshheald

WooCommerce/Classes/ViewRelated/Dashboard/Settings/In-Person Payments/CardPresentPaymentsOnboardingUseCase.swift

@@ -43,6 +43,7 @@ final class CardPresentPaymentsOnboardingUseCase: CardPresentPaymentsOnboardingU
     var statePublisher: Published<CardPresentPaymentOnboardingState>.Publisher {
         $state
     }
+    private var cancellables: [AnyCancellable] = []
 
     init(
         storageManager: StorageManagerType = ServiceLocator.storageManager,
@@ -103,11 +104,19 @@ final class CardPresentPaymentsOnboardingUseCase: CardPresentPaymentsOnboardingU
         assert(state.isSelectPlugin)
 
         preferredPluginLocal = selectedPlugin
+        deferredSaveSelectedPluginWhenOnboardingComplete(selectedPlugin: selectedPlugin)
+
         updateState()
-        if case .completed(let pluginState) = state,
-           pluginState.preferred == selectedPlugin {
-            savePreferredPlugin(selectedPlugin)
+    }
+
+    private func deferredSaveSelectedPluginWhenOnboardingComplete(selectedPlugin: CardPresentPaymentsPlugin) {
+        $state.share().sink { [weak self] newState in
+            if case .completed(let pluginState) = newState,
+               pluginState.preferred == selectedPlugin {
+                self?.savePreferredPlugin(selectedPlugin)
+            }
         }
+        .store(in: &cancellables)
     }
 
     func clearPluginSelection() {