fix: Use python3 instead of hardcoded python3.10

fix: Use python3 instead of hardcoded python3.10

Replace hardcoded python3.10 with python3 to support systems
that don't have Python 3.10 installed (e.g., Ubuntu 24.04 which
ships with Python 3.12).

This change maintains backward compatibility while enabling
builds on newer systems. Ansible 9.2.0 supports Python 3.8+,
so any python3 version will work.

Fixes: ansible-galaxy.sh failing on Ubuntu 24.04
Related: Python version fallback in global-jjb lf-env.sh

Change-Id: Ib18cf879a498a1504ff9dd25fb620ca18a0e0ed1
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>