On-demand scan detects no vulnerabilities on images build with Kaniko

Describe the bug
The indexer-app detects no vulnerabilities on images build with Kaniko.

To Reproduce

1. Create a Dockerfile:

FROM alpine:3.16

2. Build the image with Kaniko:

docker run -it --rm -v $(pwd):/workspace \
  gcr.io/kaniko-project/executor:v1.8.1-debug -f Dockerfile --no-push --tarPath kaniko.tar -d kaniko -c . --cleanup

3. Scan the image:

jf s kaniko.tar

11:47:13 [🔵Info] [Thread 2] Indexing file: kaniko.tar
11:47:16 [🔵Info]
11:47:17 [🔵Info] Waiting for scan to complete...
The full scan results are available here: /tmp/jfrog.cli.temp.-1656589638-3448319061
Note: no context was provided, so no policy could be determined to scan against.
You can get a list of custom violations by providing one of the command options: --watches, --repo-path or --project.
Read more about configuring Xray policies here: https://www.jfrog.com/confluence/display/JFROG/Creating+Xray+Policies+and+Rules
Below are all vulnerabilities detected.
┌─────────────────────────────────────┐
│ ✨ No vulnerabilities were found ✨ │
└─────────────────────────────────────┘
11:47:18 [🔵Info] Scan completed successfully.

Expected behavior
The indexer-app should detect vulnerabilities and support the image format used by Kaniko.

Versions

• JFrog CLI version: 2.19.0
• Artifactory version: 7.38.8
• Xray version: 3.48.2

Additional context
At the moment only the image format used by Docker is supported:

docker load < kaniko.tar
docker save -o docker.tar kaniko
jf s docker.tar

11:46:39 [🔵Info] [Thread 2] Indexing file: docker.tar
11:46:42 [🔵Info] 2022-06-30T11:46:40.3625282Z [jfxia] [INFO ] [] [docker_layer_tar:169          ] [main                ] Encountered release info file 'etc/alpine-release'
2022-06-30T11:46:40.3632098Z [jfxia] [INFO ] [] [docker_layer_tar:169          ] [main                ] Encountered release info file 'etc/os-release'
2022-06-30T11:46:42.9810997Z [jfxia] [INFO ] [] [tar:82                        ] [main                ] Finished indexing layers of docker /tmp/jfrog.cli.temp.-1656589599-4108843292/18502706-ce47-42ab-7307-e884cc04cf7d/165658960032915780/ (sha256:1fe6c686d3bfcc5d26158f2b946fbcd493d2f167da7b7b5cea3b0921709e5df1)

11:46:44 [🔵Info] Waiting for scan to complete...
The full scan results are available here: /tmp/jfrog.cli.temp.-1656589604-653889428
Note: no context was provided, so no policy could be determined to scan against.
You can get a list of custom violations by providing one of the command options: --watches, --repo-path or --project.
Read more about configuring Xray policies here: https://www.jfrog.com/confluence/display/JFROG/Creating+Xray+Policies+and+Rules
Below are all vulnerabilities detected.
Vulnerabilities
┌──────────┬──────────────┬────────────┬────────┬──────────┬───────────┬───────────┬────────────────┐
│ SEVERITY │ IMPACTED     │ IMPACTED   │ TYPE   │ FIXED    │ COMPONENT │ COMPONENT │ CVE            │
│          │ PACKAGE      │ PACKAGE    │        │ VERSIONS │           │ VERSION   │                │
│          │              │ VERSION    │        │          │           │           │                │
├──────────┼──────────────┼────────────┼────────┼──────────┼───────────┼───────────┼────────────────┤
│ 🔥High   │ 3.16:busybox │ 1.35.0-r13 │ Alpine │          │ kaniko    │ latest    │ CVE-2022-30065 │
└──────────┴──────────────┴────────────┴────────┴──────────┴───────────┴───────────┴────────────────┘
11:46:44 [🔵Info] Scan completed successfully.

Start with the indexer-app path used by jf s for tar images and compare how the Kaniko-generated kaniko.tar is handled with the Docker-generated docker.tar. Reproduce both scans from the issue and confirm that the Kaniko format is indexed sufficiently for the Alpine vulnerability to be reported.