update aws-secretsmanager-get-secrets to use node24

[andrewhsu]

Node20 will EOL 2026-04-30 according to release schedule. Update aws-secretsmanager-get-secrets action to use node24 instead of node20 before that date.

See github blog post:

For Actions maintainers: Update your actions to run on Node24 instead of Node20

Update to node24 will require users of github hosted runners to use version v2.237.1 or later.

Related:

• update configure-aws-credentials to use node24 configure-aws-credentials#1593
• Node.js 16 Deprecated  #69
• chore: Bump actions/upload-artifact from 4 to 6 #286