Do not check for annotation during DynamicItem registration

Since e3d23d64eb9c05305e1aa7959632da1ae2f4b98d ("Don't bind
non-annotated types into DynamicSet, DynamicMap", 2012-05-17), gerrit
has filtered out unannotated types that could belong to a DynamicSet
or DynamicMap to make it possible to write e.g. a
UniversalGroupBackend that makes use of the GroupBackends in its
DynamicSet.

DynamicItem inherited the same filter, but it isn't needed there.
Moreover, DynamicItem registration does not add a UniqueAnnotation
(since we do not want to allow multiple registrations).  Drop the
check in the DynamicItem case so implementations from plugins can
actually be loaded.

Tested using the websession-flatfile plugin.

Change-Id: Iff814bd18cad3bd5c840294591b6bffa2cd91206
1 file changed