Move metrics handler registration together with the rest of handlers, into invidious.cr

src/invidious/routing.cr

@@ -311,7 +311,6 @@ module Invidious::Routing
       # Misc
       get "/api/v1/stats", {{namespace}}::Misc, :stats
       if CONFIG.statistics_enabled
-        add_handler Metrics::METRICS_COLLECTOR
         get "/api/v1/metrics", {{namespace}}::Misc, :metrics
       end
       get "/api/v1/playlists/:plid", {{namespace}}::Misc, :get_playlist