[MM-14588] Don't mark the channel as read when adding a member (#10680)

* add flag whether to mark channel as viewed for the requesting user

* remove marking channel as viewed when adding user to a channel

app/command_invite.go

@@ -141,7 +141,7 @@ func (me *InviteProvider) DoCommand(a *App, args *model.CommandArgs, message str
 		}
 	}
 
-	if _, err := a.AddChannelMember(userProfile.Id, channelToJoin, args.Session.UserId, "", args.Session.Id); err != nil {
+	if _, err := a.AddChannelMember(userProfile.Id, channelToJoin, args.Session.UserId, ""); err != nil {
 		return &model.CommandResponse{
 			Text:         args.T("api.command_invite.fail.app_error"),
 			ResponseType: model.COMMAND_RESPONSE_TYPE_EPHEMERAL,