Some more bugfixes and small optimizations!

Optimizations:

- Impulse source storage now also uses slimlist, reducing memory allocations when there's only a single source present
- Added memory pooling to LogiX node packing, reducing memory allocations

Bugfixes:

- Fixed QuadMesh using incorrect rotation for the other side quad when using dual sided (reported by @Hayden (PolyLogiX - ZyroDesign))
- Fixed exceptions when trying to start async tasks on already disposed workers (discovered in log from @Vigilabo)
- Fixed exception when disposing FocusManager
- Fixed world not ending correctly when the link to that world from another has been disposed (discovered in log from @Vigilabo)
- Added a guard for removed slots when packing LogiX nodes. This prevents exceptions breaking the packing process (based on issue reported by @SmolCookie)
- Fixed TooltipMultiplexer using wrong tooltip offset if the multiplexed tooltip has an offset relative to it (based on report by @Aegis_Wolf)