refactor(admin_gui): break the loop early and minor style clean (#9254)

Cherry-picked from #13079

Co-authored-by: Chrono <[email protected]>

kong/admin_gui/utils.lua

@@ -7,21 +7,26 @@
 
 local _M = {}
 
+
 -- return first listener matching filters
 function _M.select_listener(listeners, filters)
   for _, listener in ipairs(listeners) do
     local match = true
+
     for filter, value in pairs(filters) do
       if listener[filter] ~= value then
         match = false
+        break
       end
     end
+
     if match then
       return listener
     end
   end
 end
 
+
 function _M.prepare_variable(variable)
   if variable == nil then
     return ""
@@ -30,4 +35,5 @@ function _M.prepare_variable(variable)
   return tostring(variable)
 end
 
+
 return _M