Remove hidden "Share on" from share links text

The share links now have "Share on" as visually hidden text by default.
This helps AT users make sense of the links (ie "Share on Facebook"
makes more sense than just "Facebook").

Therefore it is not necessary to add this visually hidden text on the
rendering app side.

app/presenters/content_item/shareable.rb

@@ -6,12 +6,12 @@ def share_links
       [
         {
           href: facebook_share_url,
-          text: '<span class="visually-hidden">Share on </span>Facebook'.html_safe,
+          text: "Facebook",
           icon: "facebook",
         },
         {
           href: twitter_share_url,
-          text: '<span class="visually-hidden">Share on </span>Twitter'.html_safe,
+          text: "Twitter",
           icon: "twitter",
         },
       ]

test/integration/consultation_test.rb

@@ -154,7 +154,7 @@ class ConsultationTest < ActionDispatch::IntegrationTest
 
   test "share urls" do
     setup_and_visit_content_item("open_consultation")
-    assert page.has_css?("a", text: "Share on Facebook")
-    assert page.has_css?("a", text: "Share on Twitter")
+    assert page.has_css?("a", text: "Facebook")
+    assert page.has_css?("a", text: "Twitter")
   end
 end