[A11Y][Wi-Fi] Fix multiple Spinner selected speak out at once.

When users select edit a Wi-Fi and select enterprise security,
there are multiple spinner shows with a default value.
This change does not allow TalkBack to speak out for multiple
Spinner text at one user selection.

Bug: 153272108
Test: manual
      Wi-Fi Settings -> Add network -> Security spinner
      -> WPA/WPA2/WPA3-Enterprise
      TalkBack should only speak out for the Security spinner.
Change-Id: Id9ab44e4da6d7abb5168e0ab7441ee1e226f5f68