Fix device linking blocking UI

src/org/thoughtcrime/securesms/ApplicationPreferencesActivity.java

@@ -26,6 +26,7 @@ import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.res.TypedArray;
 import android.graphics.drawable.Drawable;
+import android.os.AsyncTask;
 import android.os.Build;
 import android.os.Build.VERSION;
 import android.os.Bundle;
@@ -394,7 +395,7 @@ public class ApplicationPreferencesActivity extends PassphraseRequiredActionBarA
       }
 
       @Override public void sendPairingAuthorizedMessage(@NotNull PairingAuthorisation pairingAuthorisation) {
-        MultiDeviceUtilities.signAndSendPairingAuthorisationMessage(context, pairingAuthorisation);
+        AsyncTask.execute(() -> MultiDeviceUtilities.signAndSendPairingAuthorisationMessage(context, pairingAuthorisation));
       }
       @Override public void handleDeviceLinkAuthorized(@NotNull PairingAuthorisation pairingAuthorisation) {}
       @Override public void handleDeviceLinkingDialogDismissed() {}

src/org/thoughtcrime/securesms/loki/SeedActivity.kt

@@ -4,6 +4,7 @@ import android.content.ClipData
 import android.content.ClipboardManager
 import android.content.Context
 import android.content.Intent
+import android.os.AsyncTask
 import android.os.Bundle
 import android.view.View
 import android.view.inputmethod.InputMethodManager
@@ -202,9 +203,11 @@ class SeedActivity : BaseActionBarActivity(), DeviceLinkingDialogDelegate {
             application.setUpP2PAPI()
             application.setUpStorageAPIIfNeeded()
             DeviceLinkingDialog.show(this, DeviceLinkingView.Mode.Slave, this)
+            AsyncTask.execute {
                 retryIfNeeded(8) {
                     sendPairingAuthorisationMessage(this@SeedActivity, authorisation.primaryDevicePublicKey, authorisation)
                 }
+            }
         } else {
             startActivity(Intent(this, DisplayNameActivity::class.java))
             finish()