Switching from RHEL 10 to Fedora 43 breaks boot loader due to missing grub.cfg

I originally installed a machine from a RHEL 10 bootc image, which places the boot loader under `EFI/redhat/` on the EFI partition. Booting a Fedora 42 bootc image does not touch the RHEL 10 boot loader, but booting a Fedora 43 bootc image the first time does:

```
bootupctl[1646]: Previous EFI: grub2-efi-x64-1:2.12-29.el10_1.x86_64,shim-x64-15.8-5.el10_0.x86_64
bootupctl[1646]: Updated EFI: grub2-efi-x64-1:2.12-40.fc43.x86_64,shim-x64-15.8-3.x86_64
systemd[1]: Finished bootloader-update.service - Update bootloader on boot.
```

`bootupctl update` replaces the boot loader such that loader and configuration are now in separate directories:

```
# mount /dev/nvme0n1p1 /boot/efi/
# ll -R /boot/efi/
/boot/efi/:
total 4
drwxr-xr-x. 5 root root 4096 Oct 17 13:14 EFI/

/boot/efi/EFI:
total 12
drwxr-xr-x. 2 root root 4096 Oct 17 13:14 BOOT/
drwxr-xr-x. 2 root root 4096 Oct 17 13:14 fedora/
drwxr-xr-x. 2 root root 4096 Oct 17 13:14 redhat/

/boot/efi/EFI/BOOT:
total 1016
-rwxr-xr-x. 1 root root 949424 Oct 17 13:14 BOOTX64.EFI
-rwxr-xr-x. 1 root root 87816 Oct 17 13:14 fbx64.efi

/boot/efi/EFI/fedora:
total 6644
-rwxr-xr-x. 1 root root 110 Oct 17 13:14 BOOTX64.CSV
-rwxr-xr-x. 1 root root 4046144 Oct 17 13:14 grubx64.efi
-rwxr-xr-x. 1 root root 848080 Oct 17 13:14 mmx64.efi
-rwxr-xr-x. 1 root root 949424 Oct 17 13:14 shim.efi
-rwxr-xr-x. 1 root root 949424 Oct 17 13:14 shimx64.efi

/boot/efi/EFI/redhat:
total 8
-rwxr-xr-x. 1 root root 53 Oct 7 19:15 bootuuid.cfg
-rwxr-xr-x. 1 root root 657 Oct 7 19:15 grub.cfg
```

In this state, the machine fails to boot a second time since `grub.cfg` cannot be found.

The issue may be worked around by copying the configuration manually to both `EFI/fedora/` and `EFI/redhat/`, after which the machine is guaranteed to boot regardless of which boot loader was installed by `bootupctl update`.

```
mira:/boot/efi/EFI/redhat# cp -avi bootuuid.cfg grub.cfg ../fedora
'bootuuid.cfg' -> '../fedora/bootuuid.cfg'
'grub.cfg' -> '../fedora/grub.cfg'
```

Could `bootupd` be extended with some kind of hook which ensures that `grub.cfg` and `bootuuid.cfg` are always placed beside the updated boot loader, in the same directory?