attrib/gatt: Improve robustness when searching for characteristics
attrib/gatt: Improve robustness when searching for characteristics

Without this patch it is possible to enter infinite loop when searching
characteristics on remote device.
This patch fixes that.

Issue happens when remote device replies with ending handle which is
lower than start handle we use for search.

Found on robustness session on UPF50

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