select: first option without preselection announces nothing to screen readers

Bug: In Select, when no value is preselected, the first option in the list announces nothing (no position, no total) to VoiceOver + Chrome.

Repro: Use the clearable Select story (None/One/Two/Three, default Two). Open the dropdown — focus falls on None (the first option) and VoiceOver announces nothing. Moving to One correctly announces "2 of 4".

The None item is also rendered as a real dropdown option while the trigger displays "Pick an option", so it behaves like a placeholder rather than a selectable value.

Related: #4109 (fixes the count for the rest of the options) and #3962.