Includes annotations with statsd reports.

It's tricky to determine the source of the metrics on a device
currently since we can take the union of multiple configs and send
only one giant statsd_config into statsd. We will use the int64 field
to track the sub config id's and the int32 field to track the version
for each sub config, but the fields are named more generically as
annotations.

The annotations are available in both the reports and metadata.

Test: Check that all unit-tests pass on marlin-eng
Bug: 77327261
Change-Id: Ic37c549c8b2991676f69948c515156765c9f5108