TOOL-27516 LTS 24.04: Bump os-upgrade version to 9999.0

[palash-gandhi]

Problem

The version of os-upgrade Delphix engines is 999.0.0.0. For upgrade tests to work for the os-upgrade branch, the version on the appliance needs to be greater than the new versions (2025.x).

Solution

I chose 999.0 at the start of the project because we were still on the old versioning scheme and because product keys already existed at the time. Now that 9999.0.0.0 keys have been generated, move the os-upgrade branch to 9999.0.

Testing Done

http://ops.jenkins-palashgandhi.dcol2.delphix.com/job/linux-pkg/job/os-upgrade/job/build-package/job/cloud-init/job/pre-push/1/console

21:06:48  Running: configure_apt_sources
21:06:48  Running: sudo rm -rf /etc/apt/sources.list.d
21:06:48  Running: sudo apt-key add /export/home/delphix/jenkins/workspace/linux-pkg/os-upgrade/build-package/cloud-init/pre-push/linux-pkg/resources/delphix-secondary-mirror.key
21:06:48  Warning: apt-key is deprecated. Manage keyring files in trusted.gpg.d instead (see apt-key(8)).
21:06:48  OK
21:06:48  Running: sudo apt-get update
21:06:49  Hit:1 http://linux-package-mirror-v2.delphix.com/os-upgrade/bcb8a9c1/ubuntu noble InRelease
21:06:49  Hit:2 http://linux-package-mirror-v2.delphix.com/os-upgrade/bcb8a9c1/ubuntu noble-updates InRelease
21:06:49  Hit:3 http://linux-package-mirror-v2.delphix.com/os-upgrade/bcb8a9c1/ubuntu noble-security InRelease
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