snapuserd: Use GTEST_SKIP in snapuserd_test.

The test harness treats an early exit as a failure, so use GTEST_SKIP()
instead.

Bug: 379242140
Test: vts_snapuserd_test
Change-Id: I25351bb7ebf65e6c56865662d297feb4a1f635b3
(cherry picked from commit 668ffc395d0c83c9e9cdcca972e35e936a5f85f0)
1 file changed