Support preloading of fonts declared from components

Problem/Motivation

After #3366561: Support preloading of fonts in the libraries API, ensure that it also works with components.

Steps to reproduce

Declare a font in a component library overrides, check that it is preloaded.

Proposed resolution

Remaining tasks

- add test coverage for components
- handle new keys properly if needed

User interface changes

None

Introduced terminology

None

API changes

Data model changes

None

Release notes snippet