Eliminate non interested parts of content capture perf test

The ActivityTestRule#launchActivity uses startActivitySync, that
will wait until the enter animation is finished. So the metrics
are usually dominated by the animation duration. And because the
test rapidly loops launch and finish, the animation style may be
different. Then the result may not be meaningful.

Because the original purpose of the test is to ensure the frame time,
the timestamp at CALLBACK_COMMIT is more accurate. Also skip the
the animation so the test can run faster about 80%.

Bug: 258883870
Test: atest android.view.contentcapture.LoginTest
Change-Id: I529672e7a60bca8420e96d6c900d95848f94108e