Fix test so setting doesn't leak

test/web/metadata/metadata_test.exs

@@ -24,6 +24,8 @@ test "for local user" do
   end
 
   describe "no metadata for private instances" do
+    setup do: clear_config([:instance, :public])
+
     test "for local user" do
       Pleroma.Config.put([:instance, :public], false)
       user = insert(:user, bio: "This is my secret fedi account bio")