fix(apple): Move status observer setup to init() (#7673)

This is a very minor regression caused by #7555. We didn't bind the
status update observer until after the VPN profile was created. In
practice this didn't cause an issue because the status never changes
until a VPN profile is created, but still thought it's good to fix.

The JSON encoder is now configured in the `init()` as well like any
other instance variable should be.

swift/apple/FirezoneKit/Sources/FirezoneKit/Managers/TunnelManager.swift

@@ -139,6 +139,13 @@ public class TunnelManager {
   public static let bundleIdentifier: String = "\(Bundle.main.bundleIdentifier!).network-extension"
   private let bundleDescription = "Firezone"
 
+  init() {
+    encoder.outputFormat = .binary
+
+    // Hook up status updates
+    setupTunnelObservers()
+  }
+
   // Initialize and save a new VPN profile in system Preferences
   func create() async throws {
     let protocolConfiguration = NETunnelProviderProtocol()
@@ -150,7 +157,6 @@ public class TunnelManager {
     protocolConfiguration.serverAddress = settings.apiURL
     manager.localizedDescription = bundleDescription
     manager.protocolConfiguration = protocolConfiguration
-    encoder.outputFormat = .binary
 
     // Save the new VPN profile to System Preferences and reload it,
     // which should update our status from invalid -> disconnected.
@@ -203,9 +209,6 @@ public class TunnelManager {
         }
       }
 
-      // Hook up status updates
-      setupTunnelObservers()
-
       // If no tunnel configuration was found, update state to
       // prompt user to create one.
       if manager == nil {