fix: Align menu item long content with icon slots

[ling1726]

Sets flex-shrink: 0 on icon and checkmark slots

Fixes #32979

[fabricteam]

📊 Bundle size report

Package & Exports	Baseline (minified/GZIP)	PR	Change
react-components react-components: Accordion, Button, FluentProvider, Image, Menu, Popover	220.469 kB 63.821 kB	220.546 kB 63.86 kB	77 B 39 B
react-components react-components: entire library	1.159 MB 290.234 kB	1.159 MB 290.27 kB	77 B 36 B
react-menu Menu (including children components)	152.534 kB 46.049 kB	152.611 kB 46.087 kB	77 B 38 B
react-menu Menu (including selectable components)	155.215 kB 46.53 kB	155.292 kB 46.57 kB	77 B 40 B

Unchanged fixtures

Package & Exports	Size (minified/GZIP)
react-avatar Avatar	49.303 kB 15.815 kB
react-avatar AvatarGroup	20.106 kB 7.968 kB
react-avatar AvatarGroupItem	63.447 kB 20.034 kB
react-breadcrumb @fluentui/react-breadcrumb - package	114.221 kB 31.654 kB
react-components react-components: Button, FluentProvider & webLightTheme	69.14 kB 20.137 kB
react-components react-components: FluentProvider & webLightTheme	44.447 kB 14.59 kB
react-datepicker-compat DatePicker Compat	224.165 kB 63.423 kB
react-dialog Dialog (including children components)	100.247 kB 30.042 kB
react-overflow hooks only	12.808 kB 4.819 kB
react-persona Persona	56.194 kB 17.695 kB
react-popover Popover	128.854 kB 40.286 kB
react-portal-compat PortalCompatProvider	8.39 kB 2.64 kB
react-table DataGrid	161.002 kB 45.684 kB
react-table Table (Primitives only)	42.643 kB 13.82 kB
react-table Table as DataGrid	131.837 kB 36.531 kB
react-table Table (Selection only)	70.504 kB 19.962 kB
react-table Table (Sort only)	69.147 kB 19.574 kB
react-tag-picker @fluentui/react-tag-picker - package	184.106 kB 55.428 kB
react-tags InteractionTag	15.199 kB 6.157 kB
react-tags Tag	29.016 kB 9.524 kB
react-tags TagGroup	82.719 kB 24.524 kB
react-timepicker-compat TimePicker	107.387 kB 35.758 kB

_{🤖 This report was generated against ed7c93c5724087f9d2466ee2f4a01b0532d0036d}

[fabricteam]

Perf Analysis (@fluentui/react-components)

Scenario	Render type	Master Ticks	PR Ticks	Iterations	Status
FluentProviderWithTheme	virtual-rerender	37	35	10	Possible regression

All results

Scenario	Render type	Master Ticks	PR Ticks	Iterations	Status
Avatar	mount	650	613	5000
Button	mount	311	306	5000
Field	mount	1147	1122	5000
FluentProvider	mount	704	719	5000
FluentProviderWithTheme	mount	85	85	10
FluentProviderWithTheme	virtual-rerender	37	35	10	Possible regression
FluentProviderWithTheme	virtual-rerender-with-unmount	75	80	10
MakeStyles	mount	872	881	50000
Persona	mount	1769	1683	5000
SpinButton	mount	1351	1372	5000
SwatchPicker	mount	1645	1646	5000