[canary] Crash server when start black coffin in party

[Chronos77]

• [x] I have searched existing issues (https://github.com/topaz-next/topaz/issues) to see if the issue has already been opened
• [x] I have checked the commit log to see if the issue has been resolved since my server was last updated
• [x] This issue occurs on canary branch (if other branch, please specify)

Additional Information (Steps to reproduce/Expected behavior) : Make a party Start instance for black coffin

The player who doesn't start the instance has an event that has to be cancelled (with the escape key) then we have the crash server

I tried to debug however I have some questions about how to proceed. This is the luautils.cpp L 1561 -> L 1577

        sol::function onRegionLeave;
        if (PChar->PInstance)
        {
            auto instance_name = (const char*)PChar->PInstance->GetName();
            onRegionLeave      = lua["tpz"]["zones"][name]["instance"][instance_name]["onRegionLeave"];
        }
        else
        {
            onRegionLeave = lua["tpz"]["zones"][name]["Zone"]["onRegionLeave"];
        }

        if (!onRegionLeave.valid())
        {
            return -1;
        }

It crash on : onRegionLeave = lua["tpz"]["zones"][name]["instance"][instance_name]["onRegionLeave"];

Because name = arrapago_reef and instance_name = black coffin but black coffin is in the Ashu Talif zone not in arrapago.

I think i can add condition as : if (PChar->PInstance && lua["tpz"]["zones"][name]["instance"])

but i'm not sure