feat(web-components): support type ahead in Dropdown

[marchbox]

Previous Behavior

In Dropdown, when type="dropdown", typing doesn’t move active descendant to an option whose label text starts with the user typed content.

New Behavior

When Dropdown has the focus:

• If Dropdown is closed, typing will open it
• The option whose label text starts with the typed character will become the active descendant
• If multiple options can be candidates of the active descendant based on the typed character, hitting the same key will cycle through the candidate options
• If user type multiple characters within 500ms, all the characters will be buffered and used to match options

This behavior matches the native <select> and Fluent React Dropdown.

Related Issue(s)

Fixes #36122

[github-actions]

📊 Bundle size report

✅ No changes found

[github-actions]

Pull request demo site: URL

[github-actions]

🕵🏾‍♀️ visual changes to review in the Visual Change Report

vr-tests-web-components/Avatar 1 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-web-components/Avatar. - Dark Mode.normal.chromium_1.png	298	Changed

vr-tests-web-components/RadioGroup 1 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-web-components/RadioGroup. - Dark Mode.2nd selected.chromium_3.png	119	Changed

vr-tests-web-components/TextInput 1 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-web-components/TextInput. - Dark Mode.normal.chromium_1.png	288	Changed