[SPARK-49872][CORE] Remove jackson JSON string length limitation

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

This is a surgical fix extracted from apache#49163

The default jackson string limit introduced in jackson 2.15 can be too small for certain workloads, and this PR removes this limitation to avoid any regression.

### Why are the changes needed?

fix regression

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

Yes, users won't hit this size limitation anymore.

### How was this patch tested?

apache#49163 tested it. We won't add a test in this PR as generating a super large JSON will make the CI unstable.

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

no

Closes apache#52049 from cloud-fan/json.

Lead-authored-by: Wenchen Fan <wenchen@databricks.com>
Co-authored-by: Wenchen Fan <cloud0fan@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>

Author: cloud-fan

core/src/main/scala/org/apache/spark/util/JsonProtocol.scala

@@ -22,7 +22,7 @@ import java.util.{Properties, UUID}
 import scala.collection.Map
 import scala.jdk.CollectionConverters._
 
-import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.core.{JsonGenerator, StreamReadConstraints}
 import com.fasterxml.jackson.databind.JsonNode
 import org.json4s.jackson.JsonMethods.compact
 
@@ -66,6 +66,11 @@ private[spark] class JsonProtocolOptions(conf: SparkConf) {
 private[spark] object JsonProtocol extends JsonUtils {
   // TODO: Remove this file and put JSON serialization into each individual class.
 
+  // SPARK-49872: Remove jackson JSON string length limitation.
+  mapper.getFactory.setStreamReadConstraints(
+    StreamReadConstraints.builder().maxStringLength(Int.MaxValue).build()
+  )
+
   private[util]
   val defaultOptions: JsonProtocolOptions = new JsonProtocolOptions(new SparkConf(false))