[SPARK-33268][SQL][PYTHON][3.0] Fix bugs for casting data from/to PythonUserDefinedType

[maropu]

What changes were proposed in this pull request?

This PR intends to fix bugs for casting data from/to PythonUserDefinedType. A sequence of queries to reproduce this issue is as follows;

>>> from pyspark.sql import Row
>>> from pyspark.sql.functions import col
>>> from pyspark.sql.types import *
>>> from pyspark.testing.sqlutils import *
>>> 
>>> row = Row(point=ExamplePoint(1.0, 2.0))
>>> df = spark.createDataFrame([row])
>>> df.select(col("point").cast(PythonOnlyUDT()))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/maropu/Repositories/spark/spark-master/python/pyspark/sql/dataframe.py", line 1402, in select
    jdf = self._jdf.select(self._jcols(*cols))
  File "/Users/maropu/Repositories/spark/spark-master/python/lib/py4j-0.10.9-src.zip/py4j/java_gateway.py", line 1305, in __call__
  File "/Users/maropu/Repositories/spark/spark-master/python/pyspark/sql/utils.py", line 111, in deco
    return f(*a, **kw)
  File "/Users/maropu/Repositories/spark/spark-master/python/lib/py4j-0.10.9-src.zip/py4j/protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o44.select.
: java.lang.NullPointerException
	at org.apache.spark.sql.types.UserDefinedType.acceptsType(UserDefinedType.scala:84)
	at org.apache.spark.sql.catalyst.expressions.Cast$.canCast(Cast.scala:96)
	at org.apache.spark.sql.catalyst.expressions.CastBase.checkInputDataTypes(Cast.scala:267)
	at org.apache.spark.sql.catalyst.expressions.CastBase.resolved$lzycompute(Cast.scala:290)
	at org.apache.spark.sql.catalyst.expressions.CastBase.resolved(Cast.scala:290)

A root cause of this issue is that, since PythonUserDefinedType#userClassis always null, isAssignableFrom in UserDefinedType#acceptsType throws a null exception. To fix it, this PR defines acceptsType in PythonUserDefinedType and filters out the null case in UserDefinedType#acceptsType.

This backport comes from #30169.

Why are the changes needed?

Bug fixes.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Added tests.

[dongjoon-hyun]

Thanks, @maropu !

[maropu]

NOTE: I'll open a PR soon to backport it into branch-2.4., too.

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/35024/

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/35024/

[dongjoon-hyun]

+1, LGTM. Thank you, @maropu and @HyukjinKwon .
Merged to branch-3.0.

[maropu]

Thanks, all ~

[SparkQA]

Test build #130420 has finished for PR 30191 at commit 1eaff04.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.