Replace email_spec gem with built-in matchers (#38079)

spec/system/settings/two_factor_authentication_methods_spec.rb

@@ -24,17 +24,12 @@ RSpec.describe 'Settings TwoFactorAuthenticationMethods' do
 
         # Fill in challenge form
         fill_in 'form_challenge_current_password', with: user.password
-        emails = capture_emails do
-          expect { click_on I18n.t('challenge.confirm') }
-            .to change { user.reload.otp_required_for_login }.to(false)
-        end
+        expect { click_on I18n.t('challenge.confirm') }
+          .to change { user.reload.otp_required_for_login }.to(false)
+          .and send_email(to: user.email, subject: I18n.t('devise.mailer.two_factor_disabled.subject'))
 
         expect(page)
           .to have_content(I18n.t('two_factor_authentication.disabled_success'))
-        expect(emails.first)
-          .to be_present
-          .and(deliver_to(user.email))
-          .and(have_subject(I18n.t('devise.mailer.two_factor_disabled.subject')))
       end
     end
   end