Fix Launcher3Tests SDK version

In a879f9c4, the ub-launcher-aosp-tapl
was switched from current to system_current. Since Launcher3Tests links
against this library, we require it to use the system stubs as well.

But I broke the check in the build system while doing some cleanup, so
we never noticed. I'm fixing the check in:
https://android-review.googlesource.com/c/platform/build/+/1156840

Bug: 143748700
Test: treehugger
Change-Id: Ifcf47b19f7ed8f907e437325b4fd6a599fcca4cf