RepoEditor: Fix target branch dropdown styling.

app/views/shared/_target_switcher.html.haml

 - dropdown_toggle_text = @ref || @project.default_branch
-= form_tag nil, method: :get, style: { display: 'none' }, class: "project-refs-target-form" do
+= form_tag nil, method: :get, class: "project-refs-form project-refs-target-form" do
   = hidden_field_tag :destination, destination
   - if defined?(path)
     = hidden_field_tag :path, path
@@ -7,14 +7,10 @@
     = hidden_field_tag key, value, id: nil
   .dropdown
     = dropdown_toggle dropdown_toggle_text, { toggle: "dropdown", selected: dropdown_toggle_text, ref: @ref, refs_url: refs_project_path(@project, find: ['branches']), field_name: 'ref', input_field_name: 'new-branch', submit_form_on_click: true, visit: false }, { toggle_class: "js-project-refs-dropdown" }
-    %ul.dropdown-menu.dropdown-menu-selectable.git-revision-dropdown{ class: ("dropdown-menu-align-right" if local_assigns[:align_right]) }
-      %li
+    .dropdown-menu.dropdown-menu-selectable.git-revision-dropdown{ class: ("dropdown-menu-align-right" if local_assigns[:align_right]) }
       = dropdown_title _("Create a new branch")
-      %li
       = dropdown_input _("Create a new branch")
-      %li
       = dropdown_title _("Select existing branch"), options: {close: false}
-      %li
       = dropdown_filter _("Search branches and tags")
       = dropdown_content
       = dropdown_loading