[SPARK-47791][SQL][FOLLOWUP] Avoid invalid JDBC decimal scale

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

This is a follow-up of #45976 to fix a regression. Some JDBC dialects may have decimal scale larger than precision. Before #45976 , we used `DecimalType.bounded` which limits the scale to 38 and avoids this issue in some cases. But `DecimalPrecisionTypeCoercion.bounded` does not limit decimal scale and is more likely to hit the issue.

This PR proposes to make JDBC decimal scale no larger than precision. Note: we can also fix `DecimalPrecisionTypeCoercion.bounded` but I'd like to reduce the blast radius here.

### Why are the changes needed?

fix a regression that some JDBC queries start to fail after #45976

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

no, the issue is not release yet.

### How was this patch tested?

The change is very obvious, but testing needs to install other dialects so skip it

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

no

Closes #50673 from cloud-fan/decimal.

Lead-authored-by: Wenchen Fan <wenchen@databricks.com>
Co-authored-by: Wenchen Fan <cloud0fan@gmail.com>
Signed-off-by: Kent Yao <yao@apache.org>

Author: cloud-fan

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JdbcUtils.scala

@@ -203,7 +203,11 @@ object JdbcUtils extends Logging with SQLConfHelper {
     case java.sql.Types.DECIMAL | java.sql.Types.NUMERIC if scale < 0 =>
       DecimalType.bounded(precision - scale, 0)
     case java.sql.Types.DECIMAL | java.sql.Types.NUMERIC =>
-      DecimalPrecisionTypeCoercion.bounded(precision, scale)
+      DecimalPrecisionTypeCoercion.bounded(
+        // A safeguard in case the JDBC scale is larger than the precision that is not supported
+        // by Spark.
+        math.max(precision, scale),
+        scale)
     case java.sql.Types.DOUBLE => DoubleType
     case java.sql.Types.FLOAT => FloatType
     case java.sql.Types.INTEGER => if (signed) IntegerType else LongType