Use fabrication sequence in domain values (#29895)

spec/fabricators/preview_card_provider_fabricator.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 Fabricator(:preview_card_provider) do
-  domain { Faker::Internet.domain_name }
+  domain { sequence(:domain) { |i| "#{i}#{Faker::Internet.domain_name}" } }
 end

spec/fabricators/unavailable_domain_fabricator.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 Fabricator(:unavailable_domain) do
-  domain { Faker::Internet.domain_name }
+  domain { sequence(:domain) { |i| "#{i}#{Faker::Internet.domain_name}" } }
 end