Remove unneeded test (#15698)

We're revisiting the behavior of the feed scoring, and the selection
of articles will be less heavily influenced by the article's score.

This test was nested within a group related to active campaigns, but
the minimum score is a user experience setting (so if we want to test
for that it should happen outside the context), and minimum article
score will likely not be a reliable criterion for filtering the home
feed in the future.

Remove this example (it was skipped because failing), as it adds
little value and is at a minimum misplaced (wrong surrounding
context), at worst it's wrong or likely to be wrong soon.

spec/requests/stories_index_spec.rb

@@ -237,13 +237,6 @@ RSpec.describe "StoriesIndex", type: :request do
         expect(response.body).not_to include(CGI.escapeHTML("Super-sheep"))
       end
 
-      xit "doesn't display low-score posts" do
-        allow(Settings::Campaign).to receive(:sidebar_enabled).and_return(true)
-        allow(Settings::Campaign).to receive(:articles_require_approval).and_return(true)
-        get "/"
-        expect(response.body).not_to include(CGI.escapeHTML("Unapproved-post"))
-      end
-
       xit "doesn't display unapproved posts" do
         allow(Settings::Campaign).to receive(:sidebar_enabled).and_return(true)
         allow(Settings::Campaign).to receive(:sidebar_image).and_return("https://example.com/image.png")