#2157 - Updated Github Action runs-on

[k-macmillan]

Description

Modified runs-on to use a plaintext repo variable so we can set it once, everywhere. Easy to update whenever we need. After verifying 24.04 works we can change it to ubuntu-latest for all.

issue #2157

How Has This Been Tested?

Pushed then kicked off a Deploy Lambdas to Env Action to verify it grabbed the variable and used it properly.

Deployed with the updated action:

Checklist

• I have assigned myself to this PR
• PR has an appropriate title: #9999 - What the thing does
• PR has a detailed description, including links to specific documentation
• I have added the appropriate labels to the PR.
• I did not remove any parts of the template, such as checkboxes even if they are not used
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to any documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works. Testing guidelines
• I have ensured the latest main is merged into my branch and all checks are green prior to review
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• The ticket was moved into the DEV test column when I began testing this change