Increase injection timeout for InputFilterInjectionPolicyTest

This test is flaky. The test currently fails because there's no event.
To fix the test, try increasing the timeout, under the suspicion that
the host is slow.

Note: this is a speculative fix.

Bug: 282837934
Change-Id: I2f6c16013be54b38a231d721cfaea52841571a57
Test: presubmit