fix(engine): Added extra logic to safeguard devs from resurrecting stale Locs

[mark-b5]

Very small fix that should have been addressed in the last PR

[debugproc,loc_del_change]
if (p_finduid(uid) = true) {
    p_telejump(0_37_55_32_30);
    p_delay(0);
    loc_add(0_37_55_32_30, loc_1276, 0, centrepiece_straight, 10);
    p_delay(0);
    loc_del(100);
    p_delay(0);
    loc_change(loc_2732, 10);
}

Adding a static loc, deleting it, and then changing it would bring it back to life before this PR. This is an issue because a dynamic loc gets removed from the Zone when deleting (unlike a static Loc). Now, the loc_change just gets discarded via an early return 🤷