Unexpected garbage from SpawnOverDistance

Step to repro:

• Import the package in URP or HDRP project
• Enter in play mode
• Look at the profiler
• Observe the unexpected GC.Alloc coming from VFXSpawnerState.get_vfxEventAttribute

See also https://forum.unity.com/threads/spawn-over-distance-is-causing-gc-spikes.1104196/