getOfferByBasePlanId
Looks up a subscription offer by its Play Console base plan id.
Use this to pin a paywall row to a specific base plan (e.g.
"monthly" vs "yearly") rather than relying on list order. When several offers share the base plan, the first is returned — prefer the base plan's own offer by checking isBaseOffer.
Return
The matching offer, or null.
Since
4.4.0
Parameters
productId
Subscription product id.
basePlanId
Base plan id configured in Play Console.