Remove internal display related methods

Sync with changes made in SurfaceFlinger and SurfaceComposerClient.
In the case of multi-display devices, a display id must be specified
with "-d" option for screencap, since SurfaceFlinger is not guaranteed
to provide the correct default display.

Note this change breaks the default behavior of screencap, therefore
tools that rely on screencap will have to be modified to select a display to deal with multi-display devices.

Bug: 241285477
Test: manual, run screencap command to verify
Change-Id: Ibe3679d810602456205e157fe2cb8cc510062215