fix(autocomplete): apply virtual focus to first item on IME composition input (#10156)
useAutocomplete only called focusFirstItem() when inputType was
'insertText'. IME-based input (CJK languages) reports
'insertCompositionText'/'insertFromComposition' instead, which fell
through to clearVirtualFocus(true), so the first matching item never
received virtual focus and Enter could not select it.
Closes #10126