FTMGram v2.1.31

Scheme layer used: 179

• Added get_chat_sponsored_messages() and the type SponsoredMessage, by stealing unauthored changes from KurimuzonAkuma/ftmgram#55.

• Added load_group_call_participants() and the type GroupCallParticipant, by stealing unauthored changes from 6df467f.

• Added view_messages() and the bound methods read() and view().