fix: list rows line up with iOS's own row layout

[SRWieZ]

Two small layout problems with native:list-item rows on iOS, both visible in any grouped list:

1. One-line rows are not vertically centred. iOS 26 gives list cells a minimum height of 52pt. A one-line row is shorter than that, and a node fills the height it gets with its content pinned to the top, so the text sits high with a gap below it.
2. On the wide iPhones (Plus / Pro Max), rows sit 4pt to the left of their header and footer. iOS puts headers, footers and cell content on the system margin: 16pt on most iPhones, 20pt on the wide ones. List items always padded their text by 16pt.

Fix: each row keeps its own height and is centred in the list's minimum row height, and list items pad by the system margin instead of a fixed 16pt. Outside a list, a list item still pads by 16pt. Android is not touched.

To reproduce, on an iPhone 17 Pro Max simulator:

<native:list class="w-full flex-1" separator>
    <native:list-section header="General" footer="The footer text lines up with the rows above.">
        <native:list-item headline="Auto-Lock" trailingText="2 minutes" />
        <native:list-item headline="Language" trailingText="English" />
        <native:list-item headline="Sounds" :trailingSwitch="true" />
    </native:list-section>
</native:list>

Before / after (iPhone 17 Pro Max simulator, iOS 26.5): the row text moves from 16pt to 20pt inside the margin, under "General" and the footer, and the one-line rows are centred: