URL parsing assertion fails for VKontakteUserScraper

OS: Ubuntu 20.04
Python: 3.8.10
snscrape: 0.4.3.20220106

The command `snscrape vkontakte-user rus_imperia` fails after 7868 posts, because the url `'https://vk.com/wall-35251260_28090?reply=28125&thread=28091'` doesn't satisfy the `url.rsplit('_', 1)[1].strip('0123456789') in ('', '?reply=')` clause of the assertion on line 157 of snscrape.modules.vkontakte.py

One way of addressing this could be to change the assertion line from:

```
assert ...
```
to:

```
if not ...:
return
```