[cmake] Allow multiple LibEdit_LIBRARIES (#93896)

If built statically, `libedit` may have a private static library
dependency on a provider of the `terminfo` API (e.g., `ncurses`). This
means that multiple libraries would need to be provided as the value for
`LibEdit_LIBRARIES`, but the current implementation of `FindLibEdit`
precludes this. This PR allows a list to be passed to
`LibEdit_LIBRARIES`.