feat: add the coupon_codes field to CartData to track coupon redemptions for Google Ads and Google Analytics

feat: add the ItemCustomVariable resource to track per-item custom variables
feat: add merchant_id, merchant_feed_label, merchant_feed_language_code, conversion_value, and custom_variables fields to Item
feat: add the https://www.googleapis.com/auth/datamanager.partnerlink OAuth scope to PartnerLinkService
feat: add metadata fields to DeviceInfo to provide details about the user’s device
feat: add several new values to the ErrorReason enum to support store sales and Google Analytics validation
docs: update the description of transaction_id in Event to clarify its use for tag and SDK conversions
docs: update the description of enum value for PROCESSING_WARNING_REASON_USER_IDENTIFIER_DECRYPTION_ERROR to resolve typo
docs: update RequestStatus enum value descriptions to include details on error and warning information
docs: clarify population behavior for error_info and warning_info fields in RequestStatusPerDestination
feat: add third_party_user_data, event_location, and app_instance_id to Event
feat: add the MESSAGE value to the EventSource enum
feat: add mobile_device_id to AdIdentifiers for Google Analytics
feat: add a processing error reason related to BRAIDs and one-per-click conversions
feat: add youtube_members_count and gmail_members_count fields to the SizeInfo resource

PiperOrigin-RevId: 917255480

Source-Link: googleapis/googleapis@eb644cf

Source-Link: googleapis/googleapis-gen@4f030cc
Copy-Tag: eyJwIjoiQWRzRGF0YU1hbmFnZXIvLk93bEJvdC55YW1sIiwiaCI6IjRmMDMwY2M4MmU4NzE1MDZmYTNlNjkxY2I5Y2NhYjVhNmRmOWFlOTkifQ==

Author: gcf-owl-bot[bot]