Unnecessary border when CardList is embedded in a Section

[mud]

Environment

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Code Sandbox

Link to a minimal repro (fork this code sandbox):

Steps to reproduce

1. Go to the CardList interactive playground: https://blueprintjs.com/docs/#core/components/card-list.interactive-playground
2. Switch on Use section container

Actual behavior

The first card list element renders a top border with border-radius which conflicts with section header border

Expected behavior

The first card list element should not render top border, and border radius should be set to 0/none to ensure hover color doesn't show rounded corners

Possible solution