field:not(:last-child) does not work with layout builder in olivero

Problem/Motivation

This selector does not work if layout builder is used and you show several fields on content type.

.field:not(:last-child) {
    margin-block-end: var(--sp2);
}

Steps to reproduce

1. Create a few random fields on a content type.
2. Enable layout builder for your content type.
3. Reload the node
4. bottom margin is gone

Proposed resolution

Add this selector to field.css

/**
 * Content type with layout builder enabled
 */
.layout__region .block-layout-builder:not(:last-child) .field {
    margin-block-end: var(--sp2);
}

Remaining tasks

Code review

User interface changes

Before fix

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After fix

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API changes

None

Data model changes

None