This change removes the uninstall grub2-efi which was required for
prerelease rhel-9 images but now breaks current centos-9-stream
images. A different approach may be required for rhel-9 if the base
image remains different to centos-9-stream (such as populating the
empty /boot/efi partition from the base image)
This change also fixes the detection of whether this is an efi build
to check the block device instead of checking for whether a grub efi
package is installed. This fixes building a centos-9-stream whole-disk
image when package grub2-efi-x64 is installed but a legacy fallback
grub also needs to be installed.
Change-Id: I24baf553e1acd15a66737fc0b2a79d5335e28aa5
Partial-Bug: #1957789
a2cc17ad75