[ZEPPELIN-6308] Extract hardcoded py4j values to constants

### What is this PR for?
This PR extracts hardcoded py4j values to constants in Python interpreters to improve maintainability. It creates a new PythonConstants class to centralize py4j version and file path constants, replacing hardcoded strings across multiple Python interpreter classes. This addresses the TODO comment requesting to avoid hardcoded py4j values.


### What type of PR is it?
Refactoring


### Todos
* [x] - Create PythonConstants class with py4j constants
* [x] - Replace hardcoded py4j values in IPythonInterpreter
* [x] - Replace hardcoded py4j values in PythonInterpreter
* [x] - Replace hardcoded py4j values in PythonDockerInterpreter

### What is the Jira issue?
[ZEPPELIN-6308](https://issues.apache.org/jira/browse/ZEPPELIN-6308)

### How should this be tested?

### Screenshots (if appropriate)

### Questions:
* Does the license files need to update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No


Closes #5056 from celinayk/ZEPPELIN-6308.

Signed-off-by: ParkGyeongTae <gyeongtae@apache.org>

Author: celinayk

python/src/main/java/org/apache/zeppelin/python/IPythonInterpreter.java

@@ -178,10 +178,9 @@ private void initPythonInterpreter(String gatewayHost, int gatewayPort) throws I
   protected Map<String, String> setupKernelEnv() throws IOException {
     Map<String, String> envs = super.setupKernelEnv();
     if (useBuiltinPy4j) {
-      //TODO(zjffdu) don't do hard code on py4j here
-      File py4jDestFile = new File(kernelWorkDir, "py4j-src-0.10.9.7.zip");
+      File py4jDestFile = new File(kernelWorkDir, PythonConstants.PY4J_ZIP_FILENAME);
       FileUtils.copyURLToFile(getClass().getClassLoader().getResource(
-              "python/py4j-src-0.10.9.7.zip"), py4jDestFile);
+              PythonConstants.PY4J_RESOURCE_PATH), py4jDestFile);
       if (additionalPythonPath != null) {
         // put the py4j at the end, because additionalPythonPath may already contain py4j.
         // e.g. IPySparkInterpreter

python/src/main/java/org/apache/zeppelin/python/PythonConstants.java

@@ -0,0 +1,34 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.zeppelin.python;
+
+/**
+ * Constants for Python interpreters
+ */
+public class PythonConstants {
+  
+  // Py4j constants
+  public static final String PY4J_VERSION = "0.10.9.7";
+  public static final String PY4J_ZIP_FILENAME = "py4j-src-" + PY4J_VERSION + ".zip";
+  public static final String PY4J_RESOURCE_PATH = "python/" + PY4J_ZIP_FILENAME;
+  
+  private PythonConstants() {
+    // Utility class, prevent instantiation
+  }
+}
+

python/src/main/java/org/apache/zeppelin/python/PythonDockerInterpreter.java

@@ -91,7 +91,8 @@ public InterpreterResult interpret(String st, InterpreterContext context)
           ":/_zeppelin ";
 
       // set PYTHONPATH
-      String pythonPath = ".:/_python_workdir/py4j-src-0.10.9.7.zip:/_python_workdir";
+      String pythonPath = ".:/_python_workdir/" +
+          PythonConstants.PY4J_ZIP_FILENAME + ":/_python_workdir";
 
       setPythonCommand("docker run -i --rm " +
           mountPythonScript +

python/src/main/java/org/apache/zeppelin/python/PythonInterpreter.java

@@ -186,7 +186,10 @@ private void createPythonScript() throws IOException {
     copyResourceToPythonWorkDir("python/zeppelin_context.py", "zeppelin_context.py");
     copyResourceToPythonWorkDir("python/backend_zinline.py", "backend_zinline.py");
     copyResourceToPythonWorkDir("python/mpl_config.py", "mpl_config.py");
-    copyResourceToPythonWorkDir("python/py4j-src-0.10.9.7.zip", "py4j-src-0.10.9.7.zip");
+    copyResourceToPythonWorkDir(
+        PythonConstants.PY4J_RESOURCE_PATH,
+        PythonConstants.PY4J_ZIP_FILENAME);
+
   }
 
   protected boolean useIPython() {
@@ -212,7 +215,8 @@ protected Map<String, String> setupPythonEnv() throws IOException {
     Map<String, String> env = EnvironmentUtils.getProcEnvironment();
     appendToPythonPath(env, pythonWorkDir.getAbsolutePath());
     if (useBuiltinPy4j) {
-      appendToPythonPath(env, pythonWorkDir.getAbsolutePath() + "/py4j-src-0.10.9.7.zip");
+      appendToPythonPath(env,
+          pythonWorkDir.getAbsolutePath() + "/" + PythonConstants.PY4J_ZIP_FILENAME);
     }
     LOGGER.info("PYTHONPATH: {}", env.get("PYTHONPATH"));
     return env;