fix(TagPicker): add aria-disabled to expand button when disabled

[smhigley]

Previous Behavior

The expand button was the one holdout control that didn't get semantically disabled when the control is disabled

New Behavior

Adds aria-disabled! (the functionality is already handled, only the semantics were missing)

Related Issue(s)

• Fixes ADO issue

[github-actions]

📊 Bundle size report

Package & Exports	Baseline (minified/GZIP)	PR	Change
react-components react-components: entire library	1.158 MB 289.53 kB	1.158 MB 289.541 kB	32 B 11 B
react-tag-picker @fluentui/react-tag-picker - package	185.227 kB 55.684 kB	185.259 kB 55.692 kB	32 B 8 B

Unchanged fixtures

Package & Exports	Size (minified/GZIP)
react-components react-components: Button, FluentProvider & webLightTheme	69.21 kB 20.174 kB
react-components react-components: Accordion, Button, FluentProvider, Image, Menu, Popover	222.703 kB 64.42 kB
react-components react-components: FluentProvider & webLightTheme	44.447 kB 14.59 kB
react-portal-compat PortalCompatProvider	8.39 kB 2.64 kB
react-timepicker-compat TimePicker	108.525 kB 36.087 kB

_{🤖 This report was generated against d61ac31da90bf8f73f54262e196b3a83b9a85932}

[github-actions]

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