Update API of sysprop_library to match current.txt

The current.txt is updated by:
m com.android.sysprop.watchdog-dump-api && \
    rm -rf frameworks/base/core/sysprop/api/com.android.sysprop.watchdog-current.txt && \
    cp -f out/soong/.intermediates/frameworks/base/core/sysprop/com.android.sysprop.watchdog_sysprop_library/api-dump.txt \
    frameworks/base/core/sysprop/api/com.android.sysprop.watchdog-current.txt

Bug: 170935569
Test: m
Change-Id: Ie6d6ff5ed6c3883cb3459b8fb57ca18f4ce28098
Merged-In: Ie6d6ff5ed6c3883cb3459b8fb57ca18f4ce28098
(cherry picked from commit 032f11ee)