fix(decorator): validation of decorators

[dselman]

Changes

• Updates to use latest unstable concerto-core and verifies that we do not have any errors if decorators use undeclared types

Flags

• Typescript union test was modified to not use IDecorator as that type is now declared twice (once in concerto.decorator and once in meta model).

Screenshots or Video

Related Issues

• Issue #
• Pull Request #

Author Checklist

• Ensure you provide a DCO sign-off for your commits using the --signoff option of git commit.
• Vital features and changes captured in unit and/or integration tests
• Commits messages follow AP format
• Extend the documentation, if necessary
• Merging to main from fork:branchname

[coveralls]

coverage: 98.794%. remained the same
when pulling 6695b5e on ds-decorator-validation
into 9aa6167 on main.