Bluetooth: has: Fix preset list notifications after reconnection

This fixes sending proper Preset List notifications after
reconnection. The issue was observed when the last preset
known to the client has been removed.
As we do not hold the information about the deleted presets,
we need to use Generic Update procedure to:
 1. Notify the presets that have been removed in range
    (PrevIndex = current_preset_last, Index=previous_preset_last)
 2. Notify deletion of preset Index=previous_preset_last.

Signed-off-by: Mariusz Skamra <mariusz.skamra@codecoup.pl>