Mineshafts can be supported by both chain and pillars

The bug

With the new addition of chains supporting floating mineshafts, mineshafts are now able to generate with a mix of chains and pillars for the same segment of path.

How to reproduce

Seed: 1008272812876823719
Coordinates: /execute in minecraft:overworld run tp @s 2836.74 -2.00 4956.89 -80.55 4.95