Small fix

app/src/main/java/eu/faircode/email/FragmentDialogDuration.java

@@ -19,7 +19,6 @@ package eu.faircode.email;
     Copyright 2018-2019 by Marcel Bokhorst (M66B)
 */
 
-import android.app.AlertDialog;
 import android.app.Dialog;
 import android.content.DialogInterface;
 import android.content.Intent;
@@ -33,6 +32,7 @@ import android.widget.TimePicker;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.appcompat.app.AlertDialog;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.Fragment;
 

app/src/main/java/eu/faircode/email/FragmentDialogFolder.java

@@ -19,7 +19,6 @@ package eu.faircode.email;
     Copyright 2018-2019 by Marcel Bokhorst (M66B)
 */
 
-import android.app.AlertDialog;
 import android.app.Dialog;
 import android.content.Context;
 import android.content.DialogInterface;
@@ -30,6 +29,7 @@ import android.view.View;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.appcompat.app.AlertDialog;
 import androidx.fragment.app.DialogFragment;
 import androidx.fragment.app.Fragment;
 import androidx.recyclerview.widget.LinearLayoutManager;

app/src/main/java/eu/faircode/email/FragmentMessages.java

@@ -20,7 +20,6 @@ package eu.faircode.email;
 */
 
 import android.app.Activity;
-import android.app.AlertDialog;
 import android.app.Dialog;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
@@ -77,6 +76,7 @@ import android.widget.TextView;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.widget.PopupMenu;
 import androidx.appcompat.widget.SearchView;
 import androidx.constraintlayout.widget.Group;