Update `SpinButton` layout styles

[spmonahan]

Previous Behavior

Elements in SpinButton are aligned via absolute positioning.

New Behavior

Elements in SpinButton are aligned with CSS grid. Background info.

[fabricteam]

Perf Analysis (@fluentui/react-components)

Scenario	Render type	Master Ticks	PR Ticks	Iterations	Status
FluentProviderWithTheme	mount	81	89	10	Possible regression

All results

Scenario	Render type	Master Ticks	PR Ticks	Iterations	Status
Avatar	mount	653	613	5000
Button	mount	309	296	5000
Field	mount	1158	1156	5000
FluentProvider	mount	718	719	5000
FluentProviderWithTheme	mount	81	89	10	Possible regression
FluentProviderWithTheme	virtual-rerender	37	33	10
FluentProviderWithTheme	virtual-rerender-with-unmount	83	76	10
MakeStyles	mount	864	858	50000
Persona	mount	1771	1742	5000
SpinButton	mount	1374	1374	5000
SwatchPicker	mount	1520	1551	5000

[codesandbox-ci[bot]]

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[fabricteam]

📊 Bundle size report

Package & Exports	Baseline (minified/GZIP)	PR	Change
react-components react-components: entire library	1.139 MB 275.438 kB	1.139 MB 275.425 kB	-25 B -13 B
react-spinbutton SpinButton	36.78 kB 11.789 kB	36.755 kB 11.776 kB	-25 B -13 B

Unchanged fixtures

| Package & Exports | Size (minified/GZIP) | | ----------------- | -------------------: | | react-components
react-components: Button, FluentProvider & webLightTheme | `71.55 kB`
`20.584 kB` | | react-components
react-components: Accordion, Button, FluentProvider, Image, Menu, Popover | `221.825 kB`
`62.568 kB` | | react-components
react-components: FluentProvider & webLightTheme | `44.037 kB`
`14.418 kB` | | react-portal-compat
PortalCompatProvider | `8.39 kB`
`2.64 kB` |

_{🤖 This report was generated against 6e7021a53c286d6e7e5e43b5f9bad626799700ec}