Fix VTS Fuzz issue

[Description]
Fix is designed to fix VTS Fuzz issue,
1. Add null pointer check in bluetooth_hci.cc and
vendor_interface.cc
2. send should return if open is not done;
3. add lock in callback and set new callback

Bug: 247053367
Test:
1. Build Pass
2. Test VTS fuzz pass

Change-Id: I78da5aeb82f9f78b2b4a156196199183ce0dd8f2
4 files changed