Merge "Switch aidl::nullable to std::optional" into rvc-dev-plus-aosp am: ce3fd2b509 am: 668e478fda

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12325559

Change-Id: I7d6607648a1b3e9a595c8df2d62f385407882014