Remove unnecessary line

- calculate_reactive_cache does not need to initialize @prometheus_owner
again. It's already being initialized in the initialize method.

app/services/prometheus/proxy_service.rb

@@ -55,8 +55,6 @@ module Prometheus
     end
 
     def calculate_reactive_cache(prometheus_owner_class_name, prometheus_owner_id, method, path, params)
-      @prometheus_owner = prometheus_owner_from_class(prometheus_owner_class_name, prometheus_owner_id)
-
       return cannot_proxy_response unless can_proxy?(method, path)
       return no_prometheus_response unless can_query?
 
@@ -82,10 +80,6 @@ module Prometheus
       error('Proxy support for this API is not available currently')
     end
 
-    def prometheus_owner_from_class(prometheus_owner_class_name, prometheus_owner_id)
-      Kernel.const_get(prometheus_owner_class_name).find(prometheus_owner_id)
-    end
-
     def prometheus_adapter
       @prometheus_adapter ||= @prometheus_owner.prometheus_adapter
     end