Anisotropy correction external displays only

Display's EDID have rounding up to 1cm, which
results into a large uncertainty in the
screen aspect ratio. Previously 2.5% permissible
uncertainty was used but it is not enough for the
smaller displays (typically internal displays).

This CL applies anisotropy scaling only to external
displays, to make sure internal display always
use unscaled logical display.

Change-Id: Ic58f790ff3d9917b781665e3a20bac65955aeed3
Test: atest LogicalDisplayTest DisplayDeviceTest
Bug: 331562320
Bug: 317363416
Bug: 304248677