fix(settings): allow user to skip isValid startup check

[BapRx]

Problem

#4043

Solution

Add a user setting to skip this check

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[justinmk3]

See https://github.com/aws/aws-toolkit-vscode/issues/4043#issuecomment-1823008719

Is it not expected for vscode extensions to update their settings?

Instead of adding a new setting I would suggest that we store a globalState flag.

[justinmk3]

I assume this is no longer needed since https://github.com/aws/aws-toolkit-vscode/pull/4474