android/ui: unhide accounts if VPN is prepared (#406)

Updates tailscale/tailscale#12148

There was a small bug where we weren't rechecking the
vpn permissions to the FUS would never show.  We'll
now do that in the view model base case on initialization.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>

android/src/main/java/com/tailscale/ipn/ui/viewModel/IpnViewModel.kt

@@ -3,9 +3,11 @@
 
 package com.tailscale.ipn.ui.viewModel
 
+import android.net.VpnService
 import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import com.tailscale.ipn.App
 import com.tailscale.ipn.UninitializedApp
 import com.tailscale.ipn.mdm.MDMSettings
 import com.tailscale.ipn.ui.localapi.Client
@@ -36,6 +38,16 @@ open class IpnViewModel : ViewModel() {
   private var selfNodeUserId: UserID? = null
 
   init {
+    // Check if the user has granted permission yet.
+    if (!vpnPrepared.value) {
+      val vpnIntent = VpnService.prepare(App.get())
+      if (vpnIntent != null) {
+        setVpnPrepared(false)
+      } else {
+        setVpnPrepared(true)
+      }
+    }
+
     viewModelScope.launch {
       Notifier.state.collect {
         // Reload the user profiles on all state transitions to ensure loggedInUser is correct

android/src/main/java/com/tailscale/ipn/ui/viewModel/MainViewModel.kt

@@ -54,7 +54,6 @@ class MainViewModel : IpnViewModel() {
   private val peerCategorizer = PeerCategorizer()
 
   init {
-
     viewModelScope.launch {
       var previousState: State? = null
 
@@ -108,6 +107,8 @@ class MainViewModel : IpnViewModel() {
     val vpnIntent = VpnService.prepare(App.get())
     if (vpnIntent != null) {
       vpnPermissionLauncher?.launch(vpnIntent)
+    } else {
+      setVpnPrepared(true)
     }
   }
 
@@ -127,6 +128,7 @@ class MainViewModel : IpnViewModel() {
   }
 
   fun setVpnPermissionLauncher(launcher: ActivityResultLauncher<Intent>) {
+    // No intent means we're already authorized
     vpnPermissionLauncher = launcher
   }
 }