SF: Remove PhysicalDisplayId::getPort()

Work towards DisplayId opaqueness by eliminating call-sites to APIs that
parse the display ID values directly.

This CL removes PhysicalDisplayId::getPort from the PhysicalDislayId
interface entirely. The only call-sites that are dependant on port are
replaced with getting the port info via StaticDisplayInfo.

Flag: com.android.graphics.surfaceflinger.flags.stable_edid_ids
Bug: 390689635
Test: libsurfaceflinger_unittest
Change-Id: I92ea4850b158f9c49dff9166a9b61565ad4537d7