tools/mgmt-tester: Fix waiting for bthost to be ready during pre-setup stage
tools/mgmt-tester: Fix waiting for bthost to be ready during pre-setup stage

Without this it's possible we might try to enable BR/EDR SC when bthost
hasn't yet established whether the underlying controller is capable of
it.

mapfau/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,ComputeCycles/bluez,silent-snowman/bluez,ComputeCycles/bluez,ComputeCycles/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,mapfau/bluez,pkarasev3/bluez,pkarasev3/bluez,silent-snowman/bluez,mapfau/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,pkarasev3/bluez