Update GraphQL-Java to 20.7

Increase the GraphQL-Java version to 20.7 to get the newest bug fixes. See https://github.com/graphql-java/graphql-java/compare/v20.4...v20.7 for a detailed comparison of the changes in GraphQL-Java. This should be non-breaking for customers.

(CMS-23745)

Fixed headless-server-base Dependencies

Removed headless-server-p13n test dependency from headless-server-base.

(CMS-23714)