Clean up some code

- Drop stale generic

- Improve readability

Passepartout/App/Views/AddProviderView.swift

@@ -135,11 +135,11 @@ struct AddProviderView: View {
     
     // eligibility: select or purchase provider
     private func presentOrPurchaseProvider(_ metadata: ProviderMetadata) {
-        if productManager.isEligible(forProvider: metadata.name) {
-            viewModel.selectProvider(metadata, providerManager)
-        } else {
+        guard productManager.isEligible(forProvider: metadata.name) else {
             viewModel.presentPaywall()
+            return
         }
+        viewModel.selectProvider(metadata, providerManager)
     }
 
     private func onErrorMessage(_ message: String?, _ scrollProxy: ScrollViewProxy) {

PassepartoutLibrary/Sources/PassepartoutVPN/Managers/TunnelKitVPNManagerStrategy.swift

@@ -32,7 +32,7 @@ import TunnelKitOpenVPNCore
 import PassepartoutCore
 import PassepartoutUtils
 
-public class TunnelKitVPNManagerStrategy<VPNType: VPN>: VPNManagerStrategy where VPNType.Configuration == NetworkExtensionConfiguration, VPNType.Extra == NetworkExtensionExtra {
+public class TunnelKitVPNManagerStrategy: VPNManagerStrategy {
     private struct AtomicState: Equatable {
         let isEnabled: Bool
         
@@ -52,7 +52,7 @@ public class TunnelKitVPNManagerStrategy<VPNType: VPN>: VPNManagerStrategy where
     
     private let defaults: UserDefaults
 
-    private let vpn: VPNType
+    private let vpn: NetworkExtensionVPN
     
     private let dataCountInterval: TimeInterval
     
@@ -73,7 +73,7 @@ public class TunnelKitVPNManagerStrategy<VPNType: VPN>: VPNManagerStrategy where
     public init(
         appGroup: String,
         tunnelBundleIdentifier: @escaping (VPNProtocolType) -> String,
-        vpn: VPNType,
+        vpn: NetworkExtensionVPN,
         dataCountInterval: TimeInterval = 3.0
     ) {
         self.appGroup = appGroup