Fix chrome://version favicon race showing wrong icon on Origin builds
The version page favicon (IDR_PRODUCT_FAVICON) was always the standard
Brave icon regardless of Origin branding. On Origin builds this caused
the wrong icon to appear in the tab and omnibox.
Fix by copying the branding-specific product_logo_16.png as
favicon_product.png via branding.js based on isBraveOriginBranded —
the same pattern used for product_logo.png and product_logo_white.png.