[POS TPV Tracking] Send ipp_channel metadata in payment intent for IPP/POS

[jaclync]

Technical plan: pdfdoF-5QB-p2

iOS

• Send ipp_channel metadata in payment intent for IPP/POS with value mobile_store_management/mobile_pos respectively Send ipp_channel metadata in payment intent from store management/POS use cases #14479

WooPayments plugin

• Display POS channel value based on the conclusion in pdfdoF-5UW-p2 [Mobile] Display 'In-Person (POS)' for transactions from mobile POS Automattic/woocommerce-payments#9802
• Exploration: set a flag when the plugin detects a POS transaction (might require server-side changes) pdfdoF-5UW-p2#comment-6983
• Exploration: support multiple selections for the channel filter pdfdoF-5UW-p2#comment-6984

WooPayments server

• Set a transaction's channel to in_person_pos if the IPP payment's metadata ipp_channel is mobile_pos

[dangermattic]

Thanks for reporting! 👍

[wpmobilebot]

Version 21.2 has now entered code-freeze, so the milestone of this PR has been updated to 21.3.