Support the null value in bloom_filter_agg Spark aggregate function

[weixiuli]

Currently, the velox BloomFilterAggregate checks the input row and throws an exception if there are some null values in the row. So we need to be consistent with spark's behavior and ignore null values.

The spark BloomFilterAggregate will Ignore null values. https://github.com/apache/spark/blob/6cdca10f148433664b3e2be6f655b0ddba817537/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/aggregate/BloomFilterAggregate.scala#L180-L188

 override def update(buffer: BloomFilter, inputRow: InternalRow): BloomFilter = {
    val value = child.eval(inputRow)
    // Ignore null values.
    if (value == null) {
      return buffer
    }
    updater.update(buffer, value)
    buffer
  }