/boot/grub2/grubenv is missing after rear recover

Issue

• /boot/grub2/grubenv is missing after rear recover.
• Even though system can boot without /boot/grub2/grubenv, the following error output in messages files frequently.

systemd[118744]: Starting Mark boot as successful...
grub2-set-bootflag[119441]: Error canonicalizing /boot/grub2/grubenv filename: No such file or directory
systemd[118744]: grub-boot-success.service: Main process exited, code=exited, status=1/FAILURE
systemd[118744]: grub-boot-success.service: Failed with result 'exit-code'.
systemd[118744]: Failed to start Mark boot as successful.

• Install a new kernel on RHEL 8, /boot/efi/EFI/redhat/grubenv is not updated, hence the system always boots into the old kernel by default. Even if grubby --default-kernel shows the new kernel is the default.
• ReaR 2.4 doesn't have this issue.