[SPARK-49311][SQL] Make it possible for large 'interval second' value…

…s to be cast to decimal

### What changes were proposed in this pull request?

Prior to this PR, `interval second` values where the number of microseconds needed to be represented by 19 digits could not be cast to decimal. This PR removes this gap.

```
scala> sql("select 1000000000000.000000::interval second").show(false)
+---------------------------------------------+
|CAST(1000000000000.000000 AS INTERVAL SECOND)|
+---------------------------------------------+
|INTERVAL '1000000000000' SECOND              |
+---------------------------------------------+

scala> sql("select 1000000000000.000000::interval second::decimal(38, 10)").show(false)
org.apache.spark.SparkArithmeticException: [NUMERIC_VALUE_OUT_OF_RANGE.WITH_SUGGESTION]  0 cannot be represented as Decimal(18, 6). If necessary set "spark.sql.ansi.enabled" to "false" to bypass this error, and return NULL instead. SQLSTATE: 22003
```

### Why are the changes needed?

This change adds additional coverage.

### Does this PR introduce _any_ user-facing change?

Yes, users couldn't cast large second intervals to decimals earlier. Now, they can.

### How was this patch tested?

Unit test in `IntervalExpressionsSuite`.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes apache#47808 from harshmotw-db/harshmotw-db/interval_decimal_fix.

Authored-by: Harsh Motwani <harsh.motwani@databricks.com>
Signed-off-by: Max Gekk <max.gekk@gmail.com>

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/IntervalUtils.scala

@@ -902,7 +902,7 @@ object IntervalUtils extends SparkIntervalUtils {
       case DAY => Decimal(v / MICROS_PER_DAY)
       case HOUR => Decimal(v / MICROS_PER_HOUR)
       case MINUTE => Decimal(v / MICROS_PER_MINUTE)
-      case SECOND => Decimal(v, Decimal.MAX_LONG_DIGITS, 6)
+      case SECOND => Decimal(v, Decimal.MAX_LONG_DIGITS + 1, 6)
     }
   }
 

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/IntervalExpressionsSuite.scala

@@ -117,6 +117,16 @@ class IntervalExpressionsSuite extends SparkFunSuite with ExpressionEvalHelper {
     checkEvaluation(ExtractIntervalSeconds("61 seconds 1 microseconds"), Decimal(1000001, 8, 6))
   }
 
+  test("cast large seconds to decimal") {
+    checkEvaluation(
+      Cast(
+        Cast(Literal(Decimal("9223372036854.775807")), DayTimeIntervalType(3, 3)),
+        DecimalType(19, 6)
+      ),
+      Decimal("9223372036854.775807")
+    )
+  }
+
   test("multiply") {
     def check(
         interval: String,