[in_app_purchase_android] Add obfuscated profile ID support

[yuqi]

As mentioned in #130128, Google Play Billing supports passing an obfuscated profile ID in addition to an obfuscated account ID.

This adds an Android-specific obfuscatedProfileId parameter to GooglePlayPurchaseParam, and passes it through to the Play Billing flow.

final purchaseParam = GooglePlayPurchaseParam(
  productDetails: productDetails,
  applicationUserName: hashedAccountId,
  obfuscatedProfileId: hashedProfileId,
);

Fixes flutter/flutter#130128.

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Code Review

This pull request adds support for obfuscatedProfileId in the Android implementation of the in_app_purchase plugin. Specifically, it introduces the obfuscatedProfileId parameter to GooglePlayPurchaseParam, passes it through buyNonConsumable in InAppPurchaseAndroidPlatform, and updates the corresponding unit tests to verify its serialization and transmission. There are no review comments, and I have no feedback to provide.