Event for accepted to custom lfg group

[SDPhantom]

Here's what I've found that trigger the "Ready Check" sound.

LFG_LIST_JOINED_GROUP
LFG_READY_CHECK_SHOW
LFG_ROLE_CHECK_SHOW
ROLE_POLL_BEGIN

Note: LFG_PROPOSAL_SHOW is already in the table posted.
There are more PvP-related ones, but that's off-topic.