coroutines: use lifecycleScope where appropriate

There's still a bit of GlobalScope lingering around, which might be
removable.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

ui/src/main/java/com/wireguard/android/activity/TunnelToggleActivity.kt

@@ -12,13 +12,13 @@ import android.util.Log
 import android.widget.Toast
 import androidx.annotation.RequiresApi
 import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.lifecycleScope
 import com.wireguard.android.Application
 import com.wireguard.android.QuickTileService
 import com.wireguard.android.R
 import com.wireguard.android.backend.Tunnel
 import com.wireguard.android.util.ErrorMessages
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
 
 @RequiresApi(Build.VERSION_CODES.N)
@@ -26,7 +26,7 @@ class TunnelToggleActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         val tunnel = Application.getTunnelManager().lastUsedTunnel ?: return
-        GlobalScope.launch(Dispatchers.Main.immediate) {
+        lifecycleScope.launch(Dispatchers.Main.immediate) {
             try {
                 tunnel.setStateAsync(Tunnel.State.TOGGLE)
             } catch (e: Throwable) {