[zfs-2.1.10] Update vdev state for spare vdev

[ixhamza]

zfsd fetches new pool configuration through ZFS_IOC_POOL_STATS but it does not get updated nvlist configuration for spare vdev since the configuration is read by spa_spares->sav_config. In this commit, updating the vdev state for spare vdev that is consumed by zfsd on spare disk hotplug.
Openzfs PR: #14653
FreeBSD zfsd PR: freebsd/freebsd-src#697

How Has This Been Tested?

Tested on FreeBSD by spare disk hotplug and sanity test on linux

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.