protected boolean isInnerTableIdentifier(Identifier identifier) {
    if (identifier.namespace().length != 2) {
      return false;
    }
    return MixedTableStoreType.from(identifier.name()) != null;
  }
Build an Amoro {@link TableIdentifier} for the given Spark identifier.

@param identifier Spark's identifier
@return an Amoro identifier
amoro-format-mixed/amoro-mixed-spark/amoro-mixed-spark-3-common/src/main/java/org/apache/amoro/spark/mixed/MixedSparkCatalogBase.java