fix mattermost_slash_commands

spec/features/projects/services/user_activates_mattermost_slash_command_spec.rb

@@ -76,7 +76,7 @@ feature 'Setup Mattermost slash commands', :js do
       select_element = find('#mattermost_team_id')
       selected_option = select_element.find('option[selected]')
 
-      expect(select_element['disabled']).to be(true)
+      expect(select_element['disabled']).to eq("true")
       expect(selected_option).to have_content(team_name.to_s)
     end
 
@@ -104,7 +104,7 @@ feature 'Setup Mattermost slash commands', :js do
 
       select_element = find('#mattermost_team_id')
 
-      expect(select_element['disabled']).to be(false)
+      expect(select_element['disabled']).to be_falsey
       expect(select_element.all('option').count).to eq(3)
     end
 
@@ -122,7 +122,7 @@ feature 'Setup Mattermost slash commands', :js do
 
       click_link 'Add to Mattermost'
 
-      expect(find('input[type="submit"]')['disabled']).not_to be(true)
+      expect(find('input[type="submit"]')['disabled']).not_to eq("true")
     end
 
     it 'disables the submit button if the required fields are not provided', :js do
@@ -132,7 +132,7 @@ feature 'Setup Mattermost slash commands', :js do
 
       fill_in('mattermost_trigger', with: '')
 
-      expect(find('input[type="submit"]')['disabled']).to be(true)
+      expect(find('input[type="submit"]')['disabled']).to eq("true")
     end
 
     def stub_teams(count: 0)