Remove "/api" from server url after logout.

Author: nitish1211

app/src/main/java/com/zulip/android/activities/ZulipActivity.java

@@ -2123,7 +2123,7 @@ private void setNightMode(@AppCompatDelegate.NightMode int nightMode) {
     private void logout() {
         commonProgressDialog.showWithMessage(getString(R.string.logging_out));
         this.logged_in = false;
-        final String serverUrl = app.getServerURI();
+        final String serverUrl = app.getServerHostUri() ;
 
         notifications.logOut(new Runnable() {
             public void run() {