Upgrades runtime environment for lambdas in org stack to 3.11.

[vikt141]

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What does this PR do?

Upgrades Lambdas runtime to Python 3.11 for AWS org CloudFormation template

Motivation

Python 3.8 reached EOL in October 2024 https://devguide.python.org/versions/

Testing Guidelines

Used updated template with python3.11 runtime to recreate integration for AWS organisation at work