Make the ro.build.version.release consistent between device build prop & partition build prop

The ro.build.version.release has updated to use the last stable platform
version in go/ab/10260813. But the logic for per-partition build prop
has never been updated. This mismatch eventually reflects in the
device's build fingerprints and cause confusion. This cl updates the
partition build props to match the behavior of the top level build props.

Also the device's fingerprints is heavily used in static analysis, e.g.
ota targeting, the change to its computation may cause unexpected effects.

Bug: 170968068
Bug: 158483506
Test: build system image for coral, check the build prop
Change-Id: Icf741c915f2eba970258979efc274e424187ac69