fix(ui): render named group child fields when permissions.fields is empty (Closes #17812)

[waterWang]

Same fix as #17813 but for the main branch.

Description

When a named group field renders its children, it passes permissions?.fields to the inner RenderFields component. If permissions.fields is empty or missing, the inner RenderFields receives undefined or {} as permissions, causing getFieldPermissions to return read: false for all child fields — producing an empty .render-fields container.

Changes

1. Permissions fallback: When permissions.fields is empty or missing, fall back to the group's own permissions object.
2. forceRender propagation: Added missing forceRender prop to the inner RenderFields.

Closes #17812