Fix: Starting items not marked as forbidden

[SirrWilliam]

Fix for #574

I think I found the cause, but I don't know why it didn't cause this problem before. (RimWorld 1.5)
All Things were being added to the unforbidden list, whether they were forbidden or not.
Forbiddables.cs

    [HarmonyPatch(typeof(Thing), nameof(Thing.SpawnSetup))]
    static class ThingSpawnSetForbidden
    {
        static void Prefix(Thing __instance, Map map, bool respawningAfterLoad)
        {
            if (respawningAfterLoad) return;
            if (Multiplayer.Client == null) return;

            if (ThingContext.stack.Any(p => p.Item1?.def == ThingDefOf.ActiveDropPod)) return;

            if (__instance is ThingWithComps t && t.GetComp<CompForbiddable>() != null)
                map.MpComp().GetCurrentCustomFactionData().unforbidden.Add(__instance);
        }
    }

Adding !t.GetComp<CompForbiddable>().forbiddenInt to this if statement solved the problem.

 if (__instance is ThingWithComps t && t.GetComp<CompForbiddable>() != null)

I tested it on Reznal's fork because it's much more stable :D. I didn't encounter any issues.