Exclude flaky test from libvibratorservice_test presubmit

Also add postsubmit mapping to the excluded tests can be monitored and
returned to presubmit.

Bug: 293603710
Test: atest --test-mapping services/vibratorservice:presubmit
Change-Id: I4cc55a58b4b0e9f5482e300e04f8c583e62e0555