DisplayModeDirector: use configGroup when choosing default config

When calling to SurfaceFlinger to set the display config spec, the
default configId needs to consider the config group of the config.

Bug: 149784270
Test: Simulate multiple config with debug change ag/10355181
Change-Id: I50dce6e31e8cc842a221baaa69e128428f67be99
3 files changed