Add changelog: add support for kube_namespace in Metrics queries

+ small whitespace fix to better separate tests

changelogs/unreleased/pawel-add_more_variables_to_additional_metrics-35267.yml

@@ -0,0 +1,4 @@
+---
+title: Add support for kube_namespace in Metrics queries
+merge_request: 16169
+author:

spec/support/prometheus/additional_metrics_shared_examples.rb

@@ -35,6 +35,7 @@ RSpec.shared_examples 'additional metrics query' do
             environment_filter: "container_name!=\"POD\",environment=\"#{environment.slug}\""
           )
         )
+
         subject.query(*query_params)
       end
     end