[FLINK-17562][rest] Use correct headers for POST JobPlanHandler

docs/_includes/generated/rest_v1_dispatcher.html

@@ -548,7 +548,7 @@ Using 'curl' you can upload a jar via 'curl -X POST -H "Expect:" -F "jarfile=@pa
       <td class="text-left" colspan="2"><h5><strong>/jars/:jarid/plan</strong></h5></td>
     </tr>
     <tr>
-      <td class="text-left" style="width: 20%">Verb: <code>GET</code></td>
+      <td class="text-left" style="width: 20%">Verb: <code>POST</code></td>
       <td class="text-left">Response code: <code>200 OK</code></td>
     </tr>
     <tr>
@@ -579,8 +579,8 @@ Using 'curl' you can upload a jar via 'curl -X POST -H "Expect:" -F "jarfile=@pa
     </tr>
     <tr>
       <td colspan="2">
-        <button data-toggle="collapse" data-target="#550027726">Request</button>
-        <div id="550027726" class="collapse">
+        <button data-toggle="collapse" data-target="#552419128">Request</button>
+        <div id="552419128" class="collapse">
           <pre>
             <code>
 {

flink-runtime-web/src/main/java/org/apache/flink/runtime/webmonitor/WebSubmissionExtension.java

@@ -125,7 +125,7 @@ public class WebSubmissionExtension implements WebMonitorExtension {
 		webSubmissionHandlers.add(Tuple2.of(JarRunHeaders.getInstance(), jarRunHandler));
 		webSubmissionHandlers.add(Tuple2.of(JarDeleteHeaders.getInstance(), jarDeleteHandler));
 		webSubmissionHandlers.add(Tuple2.of(JarPlanGetHeaders.getInstance(), jarPlanHandler));
-		webSubmissionHandlers.add(Tuple2.of(JarPlanGetHeaders.getInstance(), postJarPlanHandler));
+		webSubmissionHandlers.add(Tuple2.of(JarPlanPostHeaders.getInstance(), postJarPlanHandler));
 	}
 
 	@Override

flink-runtime-web/src/test/resources/rest_api_v1.snapshot

@@ -318,7 +318,7 @@
     }
   }, {
     "url" : "/jars/:jarid/plan",
-    "method" : "GET",
+    "method" : "POST",
     "status-code" : "200 OK",
     "file-upload" : false,
     "path-parameters" : {