Add SafetyCenterHostSideTestCases to SC presubmits.

Previously this test would only run as presubmit on changes in the test
directory.

Will monitor for flakiness but things seem fine with the latest changes
to the directory.

Relnote: n/a
Bug: 291893003
Test: treehugger on this CL
Change-Id: I72df704c30fb450d6e1fd89b35ea8a945c545ca9