[MC-134695] 1.13 Marker tag making single Armor Stand untargetable

When setting the `Marker` tag to 1 on an armor stand, the entity no longer becomes targetable, i.e. removing said armor stand(s).
Steps to reproduce:

1. Open up a world, preferably one with no entities.
2. Enter in chat "/summon minecraft:armor_stand ~ ~ ~ {Marker:1}".
3. An armor stand should appear where you are standing.
4. Try to target it by itself.