Update Popper appendTo default to doc body

[thatblindgeye]

Describe the enhancement or change
As mentioned in patternfly/patternfly#6045 (comment) as part of some investigation/discussion, due to how we need to apply styles core-side to prevent issues with square things breaking out of rounded containers, we've decided to update Popper's default appendTo to document body. This will resolve an issue where menu-like things inside these rounded containers were being cut off/causing the containers to overflow with scrollbars.

Is this request originating from a Red Hat product team? If so, which ones and is there any sort of deadline for this enhancement?

Any other information?