Remove BTA_HF_CLIENT_SCO_LISTEN_E fallthrough

Remove unintended fallthrough.
Bug: 143901894
Test: connect SCO from both HF and AG.

Change-Id: Ifa5363479d4c844ed0b6a8585c25147b23156599
Merged-In: Ifa5363479d4c844ed0b6a8585c25147b23156599