[audio] Remove getInputForAttr usage test This test attempts to validate that getInputForAttr fails when being passed system usages, however, system usages are only relevant for outputs, not inputs, so this test is malformed. Test: atest AudioSystemUsageTest Bug: 374870131 Fixes: 379983123 Flag: EXEMPT TEST_ONLY Change-Id: Ic27c91c2286ebe7b68f9cfa01fc9bcc3feb3c483