ABC-79: Optimize channel autocomplete query (#8163)

* optimize channel autocomplete query

* move to new autocomplete endpoint

store/store.go

@@ -154,6 +154,7 @@ type ChannelStore interface {
 	AnalyticsTypeCount(teamId string, channelType string) StoreChannel
 	ExtraUpdateByUser(userId string, time int64) StoreChannel
 	GetMembersForUser(teamId string, userId string) StoreChannel
+	AutocompleteInTeam(teamId string, term string) StoreChannel
 	SearchInTeam(teamId string, term string) StoreChannel
 	SearchMore(userId string, teamId string, term string) StoreChannel
 	GetMembersByIds(channelId string, userIds []string) StoreChannel