[BUG] Fix Admin Reset Typo

PRIORITY: HIGH

Fix admin reset function setting activity to "null" instead of "none"
and causing a login freeze on attempt. This would esentially freeze the
entire server as an invalid activity was happening

app.js

@@ -413,7 +413,7 @@ app.get('/admindo', (request, response) => {
             nullLogStatus();
             nullPrezenta();
 
-            activity = 'null';
+            activity = 'none';
 
             logString = '';