Camera: fix wait for preview done timeout issue. DO NOT MERGE.

There are a couple of tests that wait for preview done but never hook up preview
callback, which cause timeout. It doesn't fail the test, but it is wrong and
causes unnecessary 5s timeout wait.

Bug: 11553138
Change-Id: I3a71003964cb750028c0f2b665cd16084f195ef2
1 file changed