Fix `RSpec/SubjectDeclaration` cop (#25312)

.rubocop_todo.yml

spec/controllers/admin/domain_blocks_controller_spec.rb

spec/models/account_migration_spec.rb

spec/models/account_spec.rb

spec/models/relationship_filter_spec.rb

spec/models/user_role_spec.rb

spec/policies/account_moderation_note_policy_spec.rb

spec/policies/account_policy_spec.rb

spec/policies/backup_policy_spec.rb

spec/policies/custom_emoji_policy_spec.rb

spec/policies/domain_block_policy_spec.rb

spec/policies/email_domain_block_policy_spec.rb

spec/policies/instance_policy_spec.rb

spec/policies/invite_policy_spec.rb

spec/policies/relay_policy_spec.rb

spec/policies/report_note_policy_spec.rb

spec/policies/report_policy_spec.rb

spec/policies/settings_policy_spec.rb

spec/policies/tag_policy_spec.rb

spec/policies/user_policy_spec.rb