No script engine guard on an event

[ksuprynowicz]

This happens on entities JS thread upon disconnection from a domain (Anime Avatars), on the "hoverLeaveEntity" event.

__pthread_kill_implementation 0x00007fffe9e9730c
ScriptEngineV8::newValue ScriptEngineV8.cpp:1218
quuidToScriptValue ScriptValueUtils.cpp:915
EntityItemIDtoScriptValue ScriptValueUtils.cpp:1084
operator() EntityScriptingInterface.cpp:175
Application::notify Application_Events.cpp:64