Since #16132, we've consolidated the setting of FORCE_UNSAFE_CONFIGURE to
`autotools.py`, so we don't need to use it in packages like `coreutils`,
in our commands, or in our container recipes.
- [x] Remove FORCE_UNSAFE_CONFIGURE from packages
- [x] Remove FORCE_UNSAFE_CONFIGURE from container recipes
- [x] Remove FORCE_UNSAFE_CONFIGURE from `spack ci` command