.github: Remove bz2 compression layer from zip artifacts

The GitHub Action artifacts are compressed zip files which include
bz2 files which are either the raw .bin images that have many zero bytes
in the rootfs but the main data in /usr is using zstd compression, or
they are the qcow2 .img images which are compressed themselves (and of
course have the same /usr compression). The bz2 compression doesn't help
in our case.
Remove the bz2 compression layer. If in the future non-zip artifacts
are supported we can add it back for the .bin image only by using
explicit calls only for that file instead of the
--image_compression_formats= flag for all images.

.github/workflows/ci.yaml

@@ -225,7 +225,7 @@ jobs:
               ./run_sdk_container -n "${container_name}" \
                   ./image_to_vm.sh --format "${format}" --board="${arch}-usr" \
                       --from "${CI_CONTAINER_ARTIFACT_ROOT}/${arch}-usr/latest" \
-                      --image_compression_formats=bz2
+                      --image_compression_formats=none
           done
 
           # Zip doesn't handle symlinks well, remove them
@@ -271,7 +271,7 @@ jobs:
           retention-days: 7
           name: ${{ matrix.arch }}-generic-image
           path: |
-            scripts/artifacts/images/flatcar_production_image.bin.bz2
+            scripts/artifacts/images/flatcar_production_image.bin
             scripts/artifacts/images/flatcar_production_image.grub
             scripts/artifacts/images/flatcar_production_image.shim
             scripts/artifacts/images/flatcar_production_image.vmlinuz
@@ -314,8 +314,8 @@ jobs:
           retention-days: 7
           name: ${{ matrix.arch }}-vm-images
           path: |
-            scripts/artifacts/images/*.img.bz2
-            scripts/artifacts/images/*.bin.bz2
+            scripts/artifacts/images/*.img
+            scripts/artifacts/images/*.bin
             scripts/artifacts/images/flatcar_production_*_efi_*.fd
             scripts/artifacts/images/*.txt
             scripts/artifacts/images/flatcar_production_*.sh

.github/workflows/run-kola-tests.yaml

@@ -162,7 +162,6 @@ jobs:
           # Extract the generic image we'll use for qemu tests.
           # Note that the qemu[_uefi] tests use the generic image instead of the
           #  qemu vendor VM image ("Astronaut: [...] Always have been.").
-          bzip2 --decompress flatcar_production_image.bin.bz2
           mv flatcar_production_image.bin flatcar_production_qemu_uefi_efi_code.fd scripts/
 
           mv flatcar_test_update.gz scripts/