Improve search of Python3 in DNF role in Aix playbook

[Haroon-Khel]

ref #3274 (comment)

In the dnf role in the AIX playbook, ansible should look for python3 in more than just /opt/freeware/bin

infrastructure/ansible/playbooks/AdoptOpenJDK_AIX_Playbook/roles/dnf/tasks/main.yml

Line 9 in 0077e29

- name: Fail if python3 is not available

- name: Fail if python3 is not available
  stat:
    path: /opt/freeware/bin/python3
  register: python3_installed
  failed_when: not python3_installed.stat.exists