Fedora ostree installer image installs broken on UEFI with 0.2.36 due to #1126

When 0.2.36 landed in Fedora Rawhide recently, ostree install tests on UEFI started failing (BIOS installs are still OK). The install apparently succeeds, but the installed system boots to the grub emergency shell.

In the install logs, we see this:

Could not find /boot/efi/EFI when installing "EFI/fedora/grub.cfg"

which looks pretty significant. Indeed if I run an install and do not reboot at the end, but go to a console and check /mnt/sysroot/boot/efi/EFI/fedora (/mnt/sysroot is where the Fedora installer mounts the installed system root) it contains no grub.cfg, which is very likely the issue. (It also seems odd that the failure to install this file is just logged as an info, but the bootupctl command still exits 0?)

On a hunch, I tested a scratch build with #1126 reverted, and it passed tests. So it looks like that PR is the cause, @Johan-Liebert1 .

I'll send an official Fedora build with the PR reverted for now, but it'd be great to get a proper fix for this. CC @cgwalters . To reproduce, just try installing from e.g. https://kojipkgs.fedoraproject.org/compose/rawhide/Fedora-Rawhide-20260821.n.0/compose/Silverblue/x86_64/iso/Fedora-Silverblue-Installer-Rawhide-20260821.n.0.x86_64.iso on a UEFI system or VM, and booting the installed system.