### What changes were proposed in this pull request?
This PR proposes to add one more newline to clearly separate JVM and Python tracebacks:
Before:
```
Traceback (most recent call last):
...
pyspark.sql.utils.AnalysisException: Reference 'column' is ambiguous, could be: column, column.;
JVM stacktrace:
org.apache.spark.sql.AnalysisException: Reference 'column' is ambiguous, could be: column, column.;
...
```
After:
```
Traceback (most recent call last):
...
pyspark.sql.utils.AnalysisException: Reference 'column' is ambiguous, could be: column, column.;
JVM stacktrace:
org.apache.spark.sql.AnalysisException: Reference 'column' is ambiguous, could be: column, column.;
...
```
This is kind of a followup of e69466056f (SPARK-31849).
### Why are the changes needed?
To make it easier to read.
### Does this PR introduce _any_ user-facing change?
It's in the unreleased branches.
### How was this patch tested?
Manually tested.
Closes#28732 from HyukjinKwon/python-minor.
Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
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