fix error handling in events and runnables

src/logic/scripting/lua/lua_engine.cpp

@@ -136,10 +136,12 @@ bool lua::emit_event(
     getglobal(L, "events");
     getfield(L, "emit");
     pushstring(L, name);
-    call_nothrow(L, args(L) + 1);
-    bool result = toboolean(L, -1);
-    pop(L, 2);
-    return result;
+    if (call_nothrow(L, args(L) + 1)) {
+        bool result = toboolean(L, -1);
+        pop(L, 2);
+        return result;
+    }
+    return false;
 }
 
 State* lua::get_main_state() {