Move the branch chooser hr

This puts the <hr> that is supposed to separate the branch
chooser from the rest of the form in the template for the
branch chooser.

That way, if the branch chooser isn't rendered, neither is the hr.

app/views/shared/issuable/_form.html.haml

@@ -14,7 +14,6 @@
 
 = render 'shared/issuable/form/branch_chooser', issuable: issuable, form: form
 
-%hr
 .form-group.row
   = form.label :title, class: 'col-form-label col-sm-2'
 

app/views/shared/issuable/form/_branch_chooser.html.haml

@@ -20,3 +20,4 @@
       = form.hidden_field(:target_branch,
         { class: 'target_branch js-target-branch-select ref-name mw-xl',
           data: { placeholder: _('Select branch'), endpoint: refs_project_path(@project, sort: 'updated_desc', find: 'branches') }})
+%hr