Add FacetsIterator#user_visible_count

This returns the total count of facets that are visible to the user,
which we need for GA4 tracking of the overall panel.

app/lib/facets_iterator.rb

@@ -7,9 +7,13 @@ def initialize(facets)
     @user_visible_facets = @facets.select(&:user_visible?)
   end
 
+  def user_visible_count
+    @user_visible_facets.count
+  end
+
   def each_with_visible_index_and_count
     @facets.each do |facet|
-      yield facet, @user_visible_facets.index(facet), @user_visible_facets.count
+      yield facet, @user_visible_facets.index(facet), user_visible_count
     end
   end
 end

spec/lib/facets_iterator_spec.rb

@@ -9,6 +9,12 @@
 
   let(:facets) { [visible_facet, hidden_facet, another_visible_facet] }
 
+  describe "#user_visible_count" do
+    it "returns the count of visible facets" do
+      expect(facets_iterator.user_visible_count).to eq(2)
+    end
+  end
+
   describe "#each_with_visible_index_and_count" do
     it "yields each facet with its index (if visible) and the total count of visible facets" do
       expect { |block| facets_iterator.each_with_visible_index_and_count(&block) }