fix: BasePickerListBelow aria-describedby with values

[smhigley]

Previous Behavior

The Picker input does not include selected items in its name or description in the ListBelow variant. This was fixed for the regular BasePicker as part of #17723.

New Behavior

The ListBelow variant now uses the same aria-describedby approach as the regular BasePicker.

Related Issue(s)

• Fixes 16181

[size-auditor]

Asset size changes

Project	Bundle	Baseline Size	New Size	Difference
office-ui-fabric-react	fluentui-react-Pickers	280.291 kB	280.489 kB	198 bytes

 Over Tolerance (1024 B)  Over Baseline  Below Baseline  New   Removed 1 kB = 1000 B

Baseline commit: 7b241289e260b97db8cd1fc4347d521a694b06d7 (build)

[codesandbox-ci]

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Latest deployment of this branch, based on commit 0e61036:

Sandbox	Source
@fluentui/react 8 starter	Configuration
@fluentui/react-components 9 starter	Configuration

[fabricteam]

📊 Bundle size report

_{🤖 This report was generated against 7b241289e260b97db8cd1fc4347d521a694b06d7}

[fabricteam]

🕵 fluentuiv8 No visual regressions between this PR and main

[fabricteam]

Perf Analysis (@fluentui/react)

No significant results to display.

All results

Scenario	Render type	Master Ticks	PR Ticks	Iterations	Status
BaseButton	mount	832	806	5000
Breadcrumb	mount	2411	2373	1000
Checkbox	mount	2185	2159	5000
CheckboxBase	mount	1902	1911	5000
ChoiceGroup	mount	3712	3742	5000
ComboBox	mount	908	891	1000
CommandBar	mount	8340	8309	1000
ContextualMenu	mount	20182	20221	1000
DefaultButton	mount	999	995	5000
DetailsRow	mount	2928	2901	5000
DetailsRowFast	mount	2924	2908	5000
DetailsRowNoStyles	mount	2679	2628	5000
Dialog	mount	3513	3508	1000
DocumentCardTitle	mount	319	328	1000
Dropdown	mount	2582	2609	5000
FocusTrapZone	mount	1506	1517	5000
FocusZone	mount	1455	1487	5000
GroupedList	mount	50429	58235	2
GroupedList	virtual-rerender	24351	24296	2
GroupedList	virtual-rerender-with-unmount	76238	76642	2
GroupedListV2	mount	324	326	2
GroupedListV2	virtual-rerender	301	304	2
GroupedListV2	virtual-rerender-with-unmount	321	329	2
IconButton	mount	1443	1440	5000
Label	mount	450	448	5000
Layer	mount	3617	3678	5000
Link	mount	530	561	5000
MenuButton	mount	1246	1243	5000
MessageBar	mount	28733	28630	5000
Nav	mount	2545	2549	1000
OverflowSet	mount	1014	1020	5000
Panel	mount	2347	2261	1000
Persona	mount	1024	987	1000
Pivot	mount	1199	1193	1000
PrimaryButton	mount	1103	1122	5000
Rating	mount	5870	5777	5000
SearchBox	mount	1195	1146	5000
Shimmer	mount	2429	2309	5000
Slider	mount	1732	1729	5000
SpinButton	mount	3792	3731	5000
Spinner	mount	526	519	5000
SplitButton	mount	2450	2452	5000
Stack	mount	535	544	5000
StackWithIntrinsicChildren	mount	1177	1145	5000
StackWithTextChildren	mount	3239	3227	5000
SwatchColorPicker	mount	8186	8245	5000
TagPicker	mount	2005	2006	5000
Text	mount	496	493	5000
TextField	mount	1203	1236	5000
ThemeProvider	mount	1162	1144	5000
ThemeProvider	virtual-rerender	795	778	5000
ThemeProvider	virtual-rerender-with-unmount	1749	1751	5000
Toggle	mount	814	803	5000
buttonNative	mount	277	286	5000