[AGENT-13568] Explicitly convert matches instead of type casting

[tbavelier]

What does this PR do?

Explicitly convert matches in the agent_version extraction to integers instead of type casting using 0 + $group. Supporting doc: https://github.com/puppetlabs/docs-archive/blob/main/puppet/4.6/function.md#conversion-to-integer

Motivation

Avoid warnings "was automatically coerced to the numerical value"

Additional Notes

• We specify radix 10 to avoid potential false radix detection (e.g. we do not want to convert to hexadecimal or other systems)
• Such warning are non-blocking UNLESS strict=error mode is enforced

Describe your test plan

Ensured you can still install specific agent versions, e.g. using agent_version => 1:7.37.1-1