Root-Canal: Fix event type sent for LE Connection completion

Previoulsy Root-Canal always notified LE connection completion
with the event LE_Connection_Complete. However the specification
indicate that LE_Enhanced_Connection_Complete should be used
in preference if the event is unmsked by the host.

This patch modifies the behaviour of HandleLeConnect to:
- Send LE_Enhanced_Connection_Complete or LE_Connection_Complete
  events only if unmasked by the host.
- Send LE_Enhanced_Connection in preference to LE_Connection_Complete
  when unmasked.

Test: PTS VCS test against Eiffel
Change-Id: Ibc90196e1ed716643e82c2c630e4c9a5354bc3ae