Extract EE-specific code from spec/factories/boards.rb

Signed-off-by: Rémy Coutable <remy@rymai.me>

ee/spec/factories/boards.rb

+FactoryBot.modify do
+  factory :board do
+    sequence(:name) { |n| "board#{n}" }
+  end
+end

spec/factories/boards.rb

 FactoryBot.define do
   factory :board do
-    sequence(:name) { |n| "board#{n}" }
-
     transient do
       project nil
       group nil