Accepts an invitation to join a party or raid. Usable in response to the
PARTY_INVITE_REQUEST event which fires when the player is invited to join a group. This function does not automatically hide the default UI's group invite dialog; doing such requires calling
StaticPopup_Hide("PARTY_INVITE"), but only after the
PARTY_MEMBERS_CHANGED event fires indicating the player has successfully joined the group.
See also Party functions, Raid functions.