Removes redundant definitions

Author: msutovsky-r7

modules/exploits/windows/http/sitecore_xp_cve_2025_34511.rb

@@ -55,7 +55,6 @@ def initialize(info = {})
 
     register_options([
       OptString.new('TARGETURI', [true, 'Path to the vulnerable endpoint', '/']),
-      OptString.new('IDENTITY_VHOST', [false, 'Hostname of Sitecore identity server'])
     ])
   end