[fix] engine: safesearch parameter in Google Videos engine (#2762)

Closes: https://github.com/searxng/searxng/issues/2762

searx/engines/google_videos.py

@@ -87,7 +87,7 @@ def request(query, params):
 
     if params['time_range'] in time_range_dict:
         query_url += '&' + urlencode({'tbs': 'qdr:' + time_range_dict[params['time_range']]})
-    if params['safesearch']:
+    if 'safesearch' in params:
         query_url += '&' + urlencode({'safe': filter_mapping[params['safesearch']]})
     params['url'] = query_url