Function: isFullSettled(AccountTypes.PerpPosition position)
This checks whether a positon has been fully settled (i.e., has no position quantity left and no cost).
Inputs
position
Control: Fully controlled by the calling function.
Constraints: Assumed to exist.
Impact: The position to check.
Branches and code coverage
Intended branches
Return whether the position is fully settled.
Assumes that there are ways of settling a position.
Assumes that after settling a position, it can no longer be interacted with.