FEATURE: Add input filter for editing tags in navigation menu modal (#22216)

What does this change do?

This commit adds an input filter to filter through the tag checkboxes in the
modal to edit tags that are shown in the user's navigation menu. The
filtering is a simple matching of the given filter term against the
names of the tags.

spec/system/editing_sidebar_tags_navigation_spec.rb

@@ -49,4 +49,24 @@ RSpec.describe "Editing sidebar tags navigation", type: :system do
     expect(sidebar).to have_no_section_link(tag2.name)
     expect(sidebar).to have_no_section_link(tag3.name)
   end
+
+  it "allows a user to filter the tags in the modal by the tag's name" do
+    visit "/latest"
+
+    expect(sidebar).to have_tags_section
+
+    modal = sidebar.click_edit_tags_button
+
+    modal.filter("tag")
+
+    expect(modal).to have_tag_checkboxes([tag, tag2, tag3])
+
+    modal.filter("tag2")
+
+    expect(modal).to have_tag_checkboxes([tag2])
+
+    modal.filter("someinvalidterm")
+
+    expect(modal).to have_no_tag_checkboxes
+  end
 end

spec/system/page_objects/modals/sidebar_edit_tags.rb

@@ -20,6 +20,14 @@ module PageObjects
           end
       end
 
+      def has_no_tag_checkboxes?
+        has_no_css?(".sidebar-tags-form-modal .sidebar-tags-form__tag") &&
+          has_css?(
+            ".sidebar-tags-form-modal .sidebar-tags-form__no-tags",
+            text: I18n.t("js.sidebar.tags_form_modal.no_tags"),
+          )
+      end
+
       def toggle_tag_checkbox(tag)
         find(
           ".sidebar-tags-form-modal .sidebar-tags-form__tag[data-tag-name='#{tag.name}'] .sidebar-tags-form__input",
@@ -32,6 +40,11 @@ module PageObjects
         find(".sidebar-tags-form-modal .sidebar-tags-form__save-button").click
         self
       end
+
+      def filter(text)
+        find(".sidebar-tags-form-modal .sidebar-tags-form__filter-input-field").fill_in(with: text)
+        self
+      end
     end
   end
 end