Fix typo on detection engine rule (elastic#56993)

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>

x-pack/legacy/plugins/siem/server/lib/detection_engine/rules/prepackaged_rules/linux_shell_activity_by_web_server.json

@@ -9,7 +9,7 @@
   "language": "kuery",
   "max_signals": 100,
   "name": "Potential Shell via Web Server",
-  "query": "process.name: bash and user.name: (apache or www or \"wwww-data\") and event.action:executed",
+  "query": "process.name: bash and user.name: (apache or www or \"www-data\") and event.action:executed",
   "references": [
     "https://pentestlab.blog/tag/web-shell/"
   ],