Add @Deprecated to DomainApplication.cloneProjectedAtTime()

DomainApplications have nothing to project, so it's a mistake to call their cloneProjectedAtTime() method.  Marking it @Deprecated helps prevent such inadvertent use.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=146716189

java/google/registry/model/domain/DomainApplication.java

@@ -169,6 +169,8 @@ public class DomainApplication extends DomainBase {
     return getRepoId();
   }
 
+  /** This is a no-op and should never be called on an application explicitly. */
+  @Deprecated
   @Override
   public DomainApplication cloneProjectedAtTime(DateTime now) {
     // Applications have no grace periods and can't be transferred, so there is nothing to project.