Replace testWidevine23FpsH264Fixed with a shorter test.

Select WidevineYouTubePerformanceTests#testL3Cenc480P30
so the test does not exceed one minute during presubmit
testing.

Requires adding @Presubmit annotation to testL3Cenc480P30.
This is because some existing tests that use @Presubmit
annotation take precedent over the rest of the tests in
TEST_MAPPING file. If we do not use @Presubmit annotation,
the new test will not be executed. Using @Presubmit annotation
has the advantage of not having to explicitly specify
testL3Cenc480P30 in the include-filter.

Test: atest --test-mapping [directory with TEST_MAPPING]
  e.g. from frameworks/av, run "atest --test-mapping drm

Bug: 168159824
Change-Id: I283ed9b1fe7f5554c4ae6c63458a954f2c7b51e1