I build custom bootc image with luks encrypted disk. The luks password is defined via kickstart file. I want to set the default keyboard layout to uncrypt disk to "fr". 
I tried 2 methods, in Containerfile : https://bootc-dev.github.io/bootc/building/kernel-arguments.html#usrlibbootckargsd

```
...
RUN echo 'kargs = ["vconsole.keymap=fr"]' > /usr/lib/bootc/kargs.d/10-vconsole-keymap.toml
...
```

And via kickstart file

```
...
autopart --encrypted --passphrase=password
bootloader --append="vconsole.keymap=fr"
...
```

For both methods, result is same : Plymouth displays "fr" below password field BUT it's still US keyboard applied


Reproducible: Always

Steps to Reproduce:
1. Build bootc image and try to setup vconsole.keymap=fr kernel argument via bootloader kickstart command or entry in /usr/lib/bootc/kargs.d/10-vconsole-keymap.toml
2. Boot
3. Try to unlock disk
Actual Results:
It's US keyboard layout used despite "fr" displayed

Expected Results:
"fr" is used

Additional Information:
/proc/cmdline shows vconsole.keymap=fr has been added but is immediately overriden by vconsole.keymap= later on the line :

```
BOOT_IMAGE=(hd0,gpt2)/ostree/default-b254461971d259b793f9af717bea03e62ce6cf261af116f00af29b3bbe3591dc/vmlinuz-6.17.8-300.fc43.x86_64 ostree=/ostree/boot.0/default/b254461971d259b793f9af717bea03e62ce6cf261af116f00af29b3bbe3591dc/0 vconsole.keymap=fr rd.luks.uuid=luks-bb31f32b-5a40-46ed-b21a-aa240d716f81 rhgb quiet root=UUID=21fae5c4-d944-49b6-8c23-89661b2817b1 vconsole.keymap= rootflags=subvol=root rw
```