Remove useless createdRepoId from logging

It is no longer needed since we don't do log-replay and it's
annoying to support in the flat flows.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=135805088

java/google/registry/flows/Flow.java

@@ -59,14 +59,6 @@ public abstract class Flow {
   /** Execute the business logic for this flow. */
   protected abstract EppOutput run() throws EppException;
 
-  /**
-   * Subclasses that create a resource should override this to return the repoId of the new
-   * resource.
-   */
-  protected String getCreatedRepoId() {
-    return null;
-  }
-
   protected String getClientId() {
     return sessionMetadata.getClientId();
   }

java/google/registry/flows/FlowRunner.java

@@ -128,7 +128,6 @@ public class FlowRunner {
                     }
                   });
       logger.info("EPP_Mutation_Committed " + new JsonLogStatement(trid)
-          .add("createdRepoId", flowResult.getResponse().getCreatedRepoId())
           .add("executionTime", flowResult.getResponse().getExecutionTime().getMillis()));
       return flowResult;
     } catch (DryRunException e) {
@@ -165,9 +164,6 @@ public class FlowRunner {
    *
    * <p>An example output for an EPP_Mutation_Committed that doesn't create a new resource:
    * {"trid":"abc-123", "executionTime":123456789}
-   *
-   * <p>An example output for an EPP_Mutation_Committed that creates a new resource:
-   * {"trid":"abc-123", "executionRepoId":123, "executionTime":123456789}
    */
   private static class JsonLogStatement {
 

java/google/registry/flows/ResourceCreateFlow.java

@@ -88,11 +88,6 @@ public abstract class ResourceCreateFlow
     modifyCreateRelatedResources();
   }
 
-  @Override
-  protected final String getCreatedRepoId() {
-    return newResource.getRepoId();
-  }
-
   /** Modify any other resources that need to be informed of this create. */
   protected void modifyCreateRelatedResources() {}