Rename DesiredDisplayModeSpecs.defaultModeId to baseModeId

This is followup from a code review comment at ag/9588196. In display
manager, each display already has a concept of a default mode id, so
rename DesiredDisplayModeSpecs.defaultModeId to baseModeId, to avoid
confusion.

Bug: 142507213

Test: atest FrameworksServicesTests:DisplayModeDirectorTest
Change-Id: I5cc137bb6f79dc120c29abda4e352e185c3aff5b
4 files changed