Check if `Script.UpdateCallIn` survives `/luaui reload`

Apparently this registration:
https://github.com/beyond-all-reason/RecoilEngine/blob/977f612eb72da12939b3413884409bbf4001e348/rts/Lua/LuaHandle.cpp#L712

survives a `/luaui reload`. Check if this happens (I just got a report and didn't verify yet). Check other related registrations (like watch weapon etc) and the other handles (luarules etc).

Ideally the initial state after a reload would be predictable and the same as the initial load, i.e. the registrations should be dropped.

Start at rts/Lua/LuaHandle.cpp around line 712 and reproduce whether Script.UpdateCallIn survives /luaui reload. Inspect related registrations such as watch weapon and the other handles, including luarules, then compare their state after reload with initial load. Done means registrations are consistently reset so reload starts from the same predictable state as initial loading.

Written by the indexing model from the issue text.