Removed SSMDefaultUser substack

[BarcoMasile]

Description

The SSMDefaultUser substack has been removed from the main stack, so it doesn't get deployed anymore, and it has been removed from the codebase.

This changes the way customer will experience the Shell action on a cluster with SSM enabled, since the user of the newly presented shell will not be the one specified in the /opt/parallelcluster/cfnconfig file as cfn_cluster_user, but it will be the default SSM user.

How Has This Been Tested?

This has been tested manually by

• deploying PCUI
• trying different dry-runs with different configs
• launching the creation of a cluster with SSM enabled
• performing miscellaneous actions on the cluster
• deleting the cluster
• deleting the whole PCUI stack with no errors

PR Quality Checklist

• I added tests to new or existing code
• I removed hardcoded strings and used react-i18next library (useTranslation hook and/or Trans component), see an example here
• I made sure no sensitive info gets logged at any time in the codebase (see here) (e.g. no user info or details, no stacktraces, etc.)
• I checked that infrastructure/update_infrastructure.sh runs without any error
• I checked that npm run build builds without any error
• I checked that clusters are listed correctly
• I checked that a new cluster can be created (config is produced and dry run passes)
• I checked that login and logout work as expected

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[mtfranchetto]

issue: update update.sh and update-environment-infra.sh as well by removing references to this file, otherwise deploys will break!

[BarcoMasile]

Nice one!! I will do asap! Thanks