make dimensions of predicted properties consistent

[wiederm]

Pull Request Summary

A few changes that are too small for a separate PR are combined here.

Key changes

Notable points that this PR has either accomplished or will accomplish.

• add ani tests for radial symmetry functions
• change shape of the energy output

Questions

• Question 1

Associated Issue(s)

• Issue 1

Pull Request Checklist

• Issue(s) raised/addressed and linked
• Includes appropriate unit test(s)
• Appropriate docstring(s) added/updated
• Appropriate .rst doc file(s) added/updated
• PR is ready for review

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.16%. Comparing base (046cf24) to head (f40b674).

Additional details and impacted files