unit/test-gatt: Add /TP/GAR/CL/BI-26-C/auto test
unit/test-gatt: Add /TP/GAR/CL/BI-26-C/auto test

/TP/GAR/CL/BI-26-C/auto is similar to /TP/GAR/CL/BI-26-C but
automatically elevates the security level and retry.

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