…google.shopping.css.v1.Attributes`

feat: A new field `headline_offer_subscription_cost` is added to message `.google.shopping.css.v1.Attributes`
feat: A new message `HeadlineOfferSubscriptionCost` is added
feat: A new message `HeadlineOfferInstallment` is added
feat: A new enum `SubscriptionPeriod` is added

PiperOrigin-RevId: 688649184

Source-Link: googleapis/googleapis@c8a7261

Source-Link: googleapis/googleapis-gen@3dcef19
Copy-Tag: eyJwIjoicGFja2FnZXMvZ29vZ2xlLXNob3BwaW5nLWNzcy8uT3dsQm90LnlhbWwiLCJoIjoiM2RjZWYxOWUzMDdiNjc5YTNmNmM4ODFkNzlmMDY0ZTg4NWZkNTJmZCJ9

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md