Update page limiter prometheus output

Now just stores a boolean of whether it was a bot or not.

app/controllers/concerns/page_limiter.rb

@@ -91,10 +91,12 @@ module PageLimiter
 
   # Record the page limit being hit in Prometheus
   def record_interception
+    dd = DeviceDetector.new(request.user_agent)
+
     Gitlab::Metrics.counter(:gitlab_page_out_of_bounds,
       controller: params[:controller],
       action: params[:action],
-      agent: request.user_agent
+      bot: dd.bot?
     )
   end
 end

spec/controllers/concerns/page_limiter_spec.rb

@@ -170,7 +170,7 @@ describe PageLimiter do
         :gitlab_page_out_of_bounds,
         controller: "explore/projects",
         action: "index",
-        agent: "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)"
+        bot: true
       )
 
       subject