libs/ui: Remove getManufacturerId() from DisplayId

There are currently no clients of DisplayId who use getManufacturerId().

This CL removes the parsing and serving of the manufacturer's ID from
DisplayID's API, together with the only client
getPnpId(PhysicalDisplayId), which also isn't use in real use cases
(only tests).

See: go/edid-display-ids-al13

Flag: com.android.graphics.surfaceflinger.flags.stable_edid_ids
Bug: 390689046
Test: Display{Id|Identification} & libsurfaceflinger_unittest
Change-Id: I03db2f6d71b32fcb387e99d9bc2730ab21760012