With the refactor of Popover to using floating-ui internally (#40740), a new placement prop was introduced with the objective of replacing the legacy position prop.

Currently, there is a function converting position to placement, but:

• its logic is complicated and difficult to follow
• its logic could potentially miss some edge cases:
  • it looks like position accepted the undocumented format [yAxis] [xAxis] [corner])
  • it looks like the new placement prop doesn't allow the Popover to be placed centered on top of its anchor
• its logic is not covered by unit tests (which makes the previous checks necessary)

Therefore, to improve the situation and get ready to deprecate the position prop, we should:

1. Assess that all possible values of position are converted correctly (or in a best-effort way) to the corresponding placement
2. Write unit tests
3. Potentially make changes to the conversion logic to respect the tests added from the previous point