dracut in Ubuntu 24.04 ignores compress="xz" and creates only uncompressed cpio initramfs

[Georgy]

I'm experiencing an issue with dracut on Ubuntu 24.04.

**Issue:**
After switching from `initramfs-tools` to `dracut`, I expected that a new initramfs would be created in dracut’s native format and (when configured) with compression, i.e., `compress="xz"`. However, regardless of settings, dracut always produces an uncompressed cpio archive as `/boot/initrd.img-$(uname -r)`.

**Steps to reproduce:**
1. Remove `initramfs-tools`
2. Install `dracut`
3. Optionally, configure `/etc/dracut.conf` with `compress="xz"`
4. Generate new initramfs.
**Expected result:**
Dracut should generate an initramfs in its compressed format (such as cpio + xz) when requested.
**Actual result:**
The generated initramfs is always an uncompressed cpio archive.
/boot/initrd.img-6.8.0-88-generic: ASCII cpio archive (SVR4 with no CRC)

**Environment:**
- Ubuntu Ubuntu 24.04.3 LTS
- dracut version: dracut 060+5-1ubuntu3.3

- Kernel: 6.8.0-88-generic

**Additional info:**
- The `/etc/alternatives/initramfs-tools` symlink does not exist.
- No traces of initramfs-tools left in the system.

Please let me know if you need more information or logs.

Bust regards, Georgy