Remove fulfilled TODO to backfill RDAP indexes

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=136062327

java/google/registry/model/host/HostResource.java

@@ -75,7 +75,6 @@ public class HostResource extends EppResource implements ForeignKeyedEppResource
    * from (creationTime, deletionTime) there can only be one host in the datastore with this name.
    * However, there can be many hosts with the same name and non-overlapping lifetimes.
    */
-  // TODO(b/25644770): Backfill this index. Until that's done, don't rely on it!
   @Index
   @XmlTransient
   String fullyQualifiedHostName;