chore: add test

Add test to ensure user sees info message if they try to add organiser without selecting one first also check the user does not see an error page

Author: davidmillen50

spec/features/admin/managing_organisers_spec.rb

@@ -39,6 +39,19 @@
       end
     end
 
+    scenario 'show flash alert warning message if user clicks add organiser without selecting an organiser from the dropdown' do
+      chapter_subscriber = Fabricate(:member)
+      chapter = Fabricate(:chapter_with_groups)
+      Fabricate(:subscription, member: chapter_subscriber, group: chapter.groups.first)
+      visit admin_chapter_organisers_path(chapter)
+
+      click_on 'Add organiser'
+
+      expect(page).to have_content('Please select a member to make organiser.')
+      expect(current_path).to eq(admin_chapter_organisers_path(chapter))
+      expect(page.status_code).to eq(200)
+    end
+
     scenario 'can remove an organiser from a chapter' do
       visit admin_chapter_organisers_path(chapter)
       organiser_name = chapter.organisers.first.full_name