incorrect grubRecoveryModeTrustedAssets for uc22 with fallback

incorrect grubRecoveryModeTrustedAssets for uc22 with fallback

https://launchpad.net/~xnox/+snap/pc-22-test/+build/1683525

contains pc-gadget implemented to boot with fallback

The gadget.yaml changes are as follows:

https://git.launchpad.net/~xnox/snap-pc/diff/gadget.yaml?h=22-focal-with-fallback&id=dbabfcfac24d8af0df37d14926f14cddaa069e67

Meaning that when booted into recovery, it will boot using:

"EFI/ubuntu/shimx64.efi"
"EFI/ubuntu/grubx64.efi"

Not using:

"EFI/boot/bootx64.efi"
"EFI/boot/grubx64.efi"

The install then fails with "cannot observe existing trusted recovery assets"

What needs to be done to update grubRecoveryModeTrustedAssets for uc22 in https://github.com/snapcore/snapd/blob/master/bootloader/grub.go#L449 ?

I wonder if it could be made dynamnic, i.e. if EFI/boot/grubx64.efi does not exist, and EFI/BOOT/fbx64.efi & EFI/ubuntu/BOOTX64.CSV do exist, use the new EFI/ubuntu/{shimx64.efi,grubx64.efi} recovery assets.