apt sources changes ignored while installing the packages

# Bug report

I'm trying to install docker (almost as per official instructions)
But after adding the docker repo, `package_update` seems to ignore the changes to repos config and installing packages like `docker-ce-cli` results in:

> [ 147.431858] cloud-init[1634]: E: Package 'docker-ce' has no installation candidate
[ 147.432992] cloud-init[1634]: E: Package 'docker-ce-cli' has no installation candidate
[ 147.434112] cloud-init[1634]: E: Unable to locate package containerd.io
[ 147.435036] cloud-init[1634]: E: Couldn't find any package by glob 'containerd.io'
[ 147.435991] cloud-init[1634]: E: Couldn't find any package by regex 'containerd.io'
[ 147.437051] cloud-init[1634]: E: Unable to locate package docker-buildx-plugin
[ 147.437987] cloud-init[1634]: E: Unable to locate package docker-compose-plugin
Logging in to the machine and installing the packages works fine (the repo is added correctly)

I found almost the same issue on [severfault](https://serverfault.com/questions/1149524/cloud-init-isnt-adding-apt-sources-before-apt-update-is-executed) that has never been resolved. Is this a bug? Is there any known workaround?

## Steps to reproduce the problem

1. Set up the cloud-config so it will add the docker repo to sources list and install packages after
2. Pass it to Ubuntu image
3. Check the logs

## Environment details
- Cloud-init version: 23.3.1-0ubuntu2
- Operating System Distribution: Ubuntu 24.04.1 LTS
- Cloud provider, platform or installer type: Yandex Cloud

## cloud-init logs

[cloud-init.tar.gz](https://github.com/user-attachments/files/17017562/cloud-init.tar.gz)