[SPARK-31480][SQL] Improve the EXPLAIN FORMATTED's output for DSV2's Scan Node
### What changes were proposed in this pull request?
Improve the EXPLAIN FORMATTED output of DSV2 Scan nodes (file based ones).
**Before**
```
== Physical Plan ==
* Project (4)
+- * Filter (3)
+- * ColumnarToRow (2)
+- BatchScan (1)
(1) BatchScan
Output [2]: [value#7, id#8]
Arguments: [value#7, id#8], ParquetScan(org.apache.spark.sql.test.TestSparkSession17477bbb,Configuration: core-default.xml, core-site.xml, mapred-default.xml, mapred-site.xml, yarn-default.xml, yarn-site.xml, hdfs-default.xml, hdfs-site.xml, __spark_hadoop_conf__.xml,org.apache.spark.sql.execution.datasources.InMemoryFileIndexa6c363ce,StructType(StructField(value,IntegerType,true)),StructType(StructField(value,IntegerType,true)),StructType(StructField(id,IntegerType,true)),[Lorg.apache.spark.sql.sources.Filter;40fee459,org.apache.spark.sql.util.CaseInsensitiveStringMapfeca1ec6,Vector(isnotnull(id#8), (id#8 > 1)),List(isnotnull(value#7), (value#7 > 2)))
(2) ...
(3) ...
(4) ...
```
**After**
```
== Physical Plan ==
* Project (4)
+- * Filter (3)
+- * ColumnarToRow (2)
+- BatchScan (1)
(1) BatchScan
Output [2]: [value#7, id#8]
DataFilters: [isnotnull(value#7), (value#7 > 2)]
Format: parquet
Location: InMemoryFileIndex[....]
PartitionFilters: [isnotnull(id#8), (id#8 > 1)]
PushedFilers: [IsNotNull(id), IsNotNull(value), GreaterThan(id,1), GreaterThan(value,2)]
ReadSchema: struct<value:int>
(2) ...
(3) ...
(4) ...
```
### Why are the changes needed?
The old format is not very readable. This improves the readability of the plan.
### Does this PR introduce any user-facing change?
Yes. the explain output will be different.
### How was this patch tested?
Added a test case in ExplainSuite.
Closes #28425 from dilipbiswal/dkb_dsv2_explain.
Lead-authored-by: Dilip Biswal <dkbiswal@gmail.com>
Co-authored-by: Dilip Biswal <dkbiswal@apache.org>
Signed-off-by: Dilip Biswal <dkbiswal@apache.org>
e4499932da