android: use updated exit node detection logic in exit node categorizer

updates tailscale/corp#29045

The exit node sorting logic wasn't using node.isMullvadNode and still
had a variant of the original issue (listing mullvad nodes as self-nodes).

This also switches the logic to ignore the name fields entirely and queue
only off the Location field matching Windows and Apple.

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

android/src/main/java/com/tailscale/ipn/ui/model/TailCfg.kt

@@ -107,13 +107,9 @@ class Tailcfg {
     val isExitNode: Boolean =
         (AllowedIPs?.contains("0.0.0.0/0") ?: false) && (AllowedIPs?.contains("::/0") ?: false)
 
-    // mullvad nodes are exit nodes with a mullvad.ts.net domain *or* Location Info.
-    // These checks are intentionally redundant to avoid false negatives.
+    // mullvad nodes are exit nodes with non-nil Location info.
     val isMullvadNode: Boolean
-      get() =
-          Name.endsWith(".mullvad.ts.net") ||
-              ComputedName?.endsWith(".mullvad.ts.net") == true ||
-              Hostinfo.Location != null
+      get() = Hostinfo.Location != null
 
     val displayName: String
       get() = ComputedName ?: Name

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

@@ -12,12 +12,12 @@ import com.tailscale.ipn.ui.model.StableNodeID
 import com.tailscale.ipn.ui.notifier.Notifier
 import com.tailscale.ipn.ui.util.LoadingIndicator
 import com.tailscale.ipn.ui.util.set
-import java.util.TreeMap
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
+import java.util.TreeMap
 
 data class ExitNodePickerNav(
     val onNavigateBackHome: () -> Unit,
@@ -75,7 +75,7 @@ class ExitNodePickerViewModel(private val nav: ExitNodePickerNav) : IpnViewModel
                             label = it.displayName,
                             online = MutableStateFlow(it.Online ?: false),
                             selected = it.StableID == exitNodeId,
-                            mullvad = it.Name.endsWith(".mullvad.ts.net."),
+                            mullvad = it.isMullvadNode,
                             priority = it.Hostinfo.Location?.Priority ?: 0,
                             countryCode = it.Hostinfo.Location?.CountryCode ?: "",
                             country = it.Hostinfo.Location?.Country ?: "",