Add mainline kernel upgarde support for ubuntu

[linhuali]

• Add upgrade_kernel_version into var/test.yml for testing kernel upgrade only in ubuntu
• Testing done with ubuntu 24.04 and mainline kernel 6.11-rc2

  ok: [localhost] => {
  "ansible_facts": {
      "upgrade_kernel_version": "6.11-rc2"
  },
  "changed": false
  }
  ...
  ok: [localhost] => {
  "ansible_facts": {
      "kernel_before_upgrade": "6.8.0-39-generic",
      "kernel_is_upgraded": false
  },
  "changed": false
  }
  ...
  ok: [localhost] => {
  "ansible_facts": {
      "kernel_after_upgrade": "6.11.0-061100rc2-generic"
  },
  "changed": false
  }