fix(starbase): Fix in validation logic of custom domains in getAppPublicProps

[betimshahini]

Description

Fix in validation logic of custom domains in getAppPublicProps, where it wouldn't return a boolean value in the evaluation expression, but undefined or null. Without the fix, errors are thrown for cases of a non-custom domain lookup.

Related Issues

• N/A

Testing

• Invoked functionality that looks up AppProps (by logging on to an app). Was able to successfully get to the login page.

Checklist

• I have read the CONTRIBUTING guidelines
• I have tested my code (manually and/or automated if applicable)
• I have updated the documentation (if necessary)