res_sorcery_astdb: Filter fields to only the registered ones.

res_sorcery_astdb: Filter fields to only the registered ones.

This change introduces the same filtering that is done in res_sorcery_realtime
to the res_sorcery_astdb module. This allows persisted sorcery objects
that may contain unknown fields to still be read in from the AstDB
and used. This is particularly useful when switching between different
versions of Asterisk that may have introduced additional fields.

ASTERISK-26014 #close

Change-Id: Ib655130485a3ccfd635b7ed5546010ca14690fb2