Build *-helper libs with LOCAL_SDK_VERSION := current

The helper libs has been built without LOCAL_SDK_VERSION, which
triggered link-type check warning from system-helpers; java:sdk ->
java:platform dependency is not allowed and will trigger errors instead
of warnings soon.

Bug: 69899800
Test: mma -j under platform_testing/libraries/system-helpers
build is successful

Merged-In I8261d487933594aa4aee3398fce1923ba07cb3b4
Change-Id: I8261d487933594aa4aee3398fce1923ba07cb3b4