Write a method that swaps the first and last elements in an ArrayList of Strings.

For example, if we had an ArrayList list with the values $[$hello$,$world$]$:

swapFirstLast$($list$)$

Should return an ArrayList with the elements:

$["$world$",$ "hello"$]$

If we had an ArrayList list with the values $[$hello$]$:

swapFirstLast$($list$)$

Should return an array with the elements:

$["$hello$"]$

swapFirstLast$($new ArrayList$())$

Should return an empty ArrayList:

$[]$