fix: add xmlns and xmlnsXlink to SvgProps types (#1638)

[patrickwehbe]

Summary

Closes #1638.

Using xmlns (and xmlnsXlink) on <Svg> raises a TypeScript error:

TS2322: Property 'xmlns' does not exist on type 'IntrinsicAttributes & ...'

This is the standard output of SVGO and most web/SVG export tools, so people
who paste an optimized SVG component hit the error immediately:

<Svg xmlns="http://www.w3.org/2000/svg" width={1242.667} height={974.667} viewBox="0 0 932 731">
  <Path d="..." />
</Svg>

SvgProps already accepts other root-only attributes like viewBox and
preserveAspectRatio, but not the namespace attributes. This adds them as
optional strings. They are inert in the native renderer (no behavior change),
so this is purely a type-surface fix that lets the standard exported markup
type-check.

Test Plan

<Svg xmlns="http://www.w3.org/2000/svg" xmlnsXlink="http://www.w3.org/1999/xlink" />
fails yarn tsc before this change and passes after.

• yarn tsc passes
• yarn lint passes

Compatibility

OS	Implemented
iOS	N/A
MacOS	N/A
Android	N/A
Web	N/A

Type-only change; no platform code affected.

Checklist

• I have tested this on a device and a simulator
• I added documentation in README.md
• I updated the typed files (typescript)
• I added a test for the API in the __tests__ folder