Remove all Ravenwood annotations in SystemUiRavenTests

Currently a significant amount of APIs used in SystemUiRavenTests are
not supported and under active development, so to reduce churn on the
SysUi team, this test module is not included in any TEST_MAPPING. This
means that SystemUiRavenTests is actually a fast moving target, with
tests sporadically pass/fail on any changes to the SysUi codebase.

This makes adding Ravenwood test enablement annotations directly inside
the SysUi codebase less meaningful as nobody other than the Ravenwood
team is running and tracking the status of SystemUiRavenTests (at least
this will continue to be the case for the near future).

The Ravenwood team still uses SystemUiRavenTests internally as a
baseline to help prioritizing their effort, so test enablement and
passing status will be tracked externally in a text file under
f/b/r/texts/sysui-enablement-policy.txt, and SystemUiRavenTests will
only be executed in local checkouts via the
f/b/r/scripts/run-sysui-tests.sh script.

Once Ravenwood's API support is robust enough for SysUi use cases, we
will re-introduce annotations back into SysUi codebase and start adding
SystemUiRavenTests into TEST_MAPPINGs.

Bug: 319647875
Flag: TEST_ONLY
Test: f/b/r/scripts/run-sysui-tests.sh
Change-Id: Ide4828b63703d302edfe21fa01afd61a2b88b294