Parcel: deprecate unique_ptr read/write methods

Since Android R, Parcel provides read/write methods for "@nullable"
values using std::optional. Deprecating "unique_ptr" versions
so that the compiler emits errors like following when trying to use
unique_ptr variants:

  error: 'readUtf8FromUtf16' is deprecated: use std::optional
      version instead [-Werror,-Wdeprecated-declarations]

Note that parcel_puzzer/binder.cpp still tests deprecated functions.

Bug: 149784838
Test: m
Change-Id: I65fc58333373ce04a871dd5cdbe4b761ce548393