fix: Overlay NavDrawer needs to preserve dialog role

[smhigley]

Previous Behavior

The overlay variant of NavDrawer overrode the underlying Drawer's role=dialog, which is required for a lot of built-in screen reader behavior around virtual cursor behavior and setting user expectations for being in a modal dialog. Without the role, aria-modal=true also doesn't really do anything.

New Behavior

NavDrawer keeps role=dialog, and the role=navigation is moved to NavDrawerBody. While that means the header is no longer part of the navigation region, that seems generally fine to me.

Related Issue(s)

None, noticed this while working on a different FAI bug.

[github-actions]

📊 Bundle size report

Package & Exports	Baseline (minified/GZIP)	PR	Change
react-components react-components: entire library	1.274 MB 321.042 kB	1.274 MB 321.042 kB	5 B

Unchanged fixtures

Package & Exports	Size (minified/GZIP)
react-components react-components: Button, FluentProvider & webLightTheme	68.79 kB 19.902 kB
react-components react-components: Accordion, Button, FluentProvider, Image, Menu, Popover	235.675 kB 68.193 kB
react-components react-components: FluentProvider & webLightTheme	43.624 kB 14.255 kB
react-portal-compat PortalCompatProvider	8.386 kB 2.624 kB
react-timepicker-compat TimePicker	109.052 kB 36.053 kB

_{🤖 This report was generated against ea2fbd636af8cd5d6b78448c595f9d102ca8a1f9}

[github-actions]

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