[KYUUBI #3527][SPARK][FOLLOWUP] spark.kubernetes.executorEnv should be spark.executorEnv

### _Why are the changes needed?_

Fix bug in #3527
Modify `spark.kubernetes.executorEnv` to `spark.executorEnv`

### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

- [ ] Add screenshots for manual tests if appropriate

- [ ] [Run test](https://kyuubi.apache.org/docs/latest/develop_tools/testing.html#running-tests) locally before make a pull request
- [x] Unit Test

Closes #3591 from zwangsheng/follow/SPARK_USER_NAME.

Closes #3527

7254fe9 [zwangsheng] fix executorEnv

Authored-by: zwangsheng <[email protected]>
Signed-off-by: Cheng Pan <[email protected]>

Author: zwangsheng

kyuubi-server/src/main/scala/org/apache/kyuubi/engine/spark/SparkProcessBuilder.scala

@@ -98,7 +98,7 @@ class SparkProcessBuilder(
           buffer += CONF
           buffer += s"spark.kubernetes.driverEnv.SPARK_USER_NAME=$userName"
           buffer += CONF
-          buffer += s"spark.kubernetes.executorEnv.SPARK_USER_NAME=$userName"
+          buffer += s"spark.executorEnv.SPARK_USER_NAME=$userName"
         }
       })
     }

kyuubi-server/src/test/scala/org/apache/kyuubi/engine/spark/SparkProcessBuilderSuite.scala

@@ -277,7 +277,7 @@ class SparkProcessBuilderSuite extends KerberizedTestHelper with MockitoSugar {
     val b1 = new SparkProcessBuilder(proxyName, conf1)
     val c1 = b1.toString.split(' ')
     assert(c1.contains(s"spark.kubernetes.driverEnv.SPARK_USER_NAME=$proxyName"))
-    assert(c1.contains(s"spark.kubernetes.executorEnv.SPARK_USER_NAME=$proxyName"))
+    assert(c1.contains(s"spark.executorEnv.SPARK_USER_NAME=$proxyName"))
 
     tryWithSecurityEnabled {
       val conf2 = conf.set("spark.master", "k8s://test:12345")
@@ -287,7 +287,7 @@ class SparkProcessBuilderSuite extends KerberizedTestHelper with MockitoSugar {
       val b2 = new SparkProcessBuilder(name, conf2)
       val c2 = b2.toString.split(' ')
       assert(c2.contains(s"spark.kubernetes.driverEnv.SPARK_USER_NAME=$name"))
-      assert(c2.contains(s"spark.kubernetes.executorEnv.SPARK_USER_NAME=$name"))
+      assert(c2.contains(s"spark.executorEnv.SPARK_USER_NAME=$name"))
       assert(!c2.contains(s"--proxy-user $name"))
     }
 
@@ -296,7 +296,7 @@ class SparkProcessBuilderSuite extends KerberizedTestHelper with MockitoSugar {
     val b3 = new SparkProcessBuilder(proxyName, conf3)
     val c3 = b3.toString.split(' ')
     assert(!c3.contains(s"spark.kubernetes.driverEnv.SPARK_USER_NAME=$proxyName"))
-    assert(!c3.contains(s"spark.kubernetes.executorEnv.SPARK_USER_NAME=$proxyName"))
+    assert(!c3.contains(s"spark.executorEnv.SPARK_USER_NAME=$proxyName"))
   }
 }