[SPARK-27869][CORE] Redact sensitive information in System Properties…

… from UI

## What changes were proposed in this pull request?

Currently system properties are not redacted. This PR fixes that, so that any credentials passed as System properties are redacted as well.

## How was this patch tested?

Manual test. Run the following and see the UI.
```
bin/spark-shell --conf 'spark.driver.extraJavaOptions=-DMYSECRET=app'
```

Closes #24733 from aaruna/27869.

Authored-by: Aaruna <aaruna.godthi@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

core/src/main/scala/org/apache/spark/ui/env/EnvironmentPage.scala

@@ -44,8 +44,8 @@ private[ui] class EnvironmentPage(
       Utils.redact(conf, appEnv.sparkProperties.sorted), fixedWidth = true)
     val hadoopPropertiesTable = UIUtils.listingTable(propertyHeader, propertyRow,
       Utils.redact(conf, appEnv.hadoopProperties.sorted), fixedWidth = true)
-    val systemPropertiesTable = UIUtils.listingTable(
-      propertyHeader, propertyRow, appEnv.systemProperties.sorted, fixedWidth = true)
+    val systemPropertiesTable = UIUtils.listingTable(propertyHeader, propertyRow,
+      Utils.redact(conf, appEnv.systemProperties.sorted), fixedWidth = true)
     val classpathEntriesTable = UIUtils.listingTable(
       classPathHeaders, classPathRow, appEnv.classpathEntries.sorted, fixedWidth = true)
     val content =