Problem/Motivation
When accessing Layout Builder overrides via REST (i.e. when accessing an overridden entity's layout field), the contents of sections are empty.
Proposed resolution
Add a normalizer for the layout_section DataType, which ensures that sections can be properly serialized and unserialized via the serialization API (and REST).
Remaining tasks
N/A
User interface changes
N/A
API changes
A new normalizer will be added for the layout_section DataType.
Layout section data will be exposed for all serialization types.
Data model changes
N/A