[FIXED JENKINS-40848] Introduce status indicator for skipped download job (#2705)

* [FIXED JENKINS-40848] Introduce status indicator for skipped download job

* [JENKINS-40848] Stick to existing code-flow as that is proved to work

core/src/main/java/hudson/model/UpdateCenter.java

@@ -1870,7 +1870,6 @@ public class UpdateCenter extends AbstractModelObject implements Saveable, OnMas
                 // Do this first so we can avoid duplicate downloads, too
                 // check to see if the plugin is already installed at the same version and skip it
                 LOGGER.info("Skipping duplicate install of: " + plugin.getDisplayName() + "@" + plugin.version);
-                //throw new Skipped(); // TODO set skipped once we have a status indicator for it
                 return;
             }
             try {

core/src/main/resources/hudson/model/UpdateCenter/DownloadJob/Skipped/status.jelly

+<!--
+The MIT License
+
+Copyright (c) 2004-2009, Sun Microsystems, Inc., Kohsuke Kawaguchi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+-->
+
+<?jelly escape-by-default='true'?>
+<j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
+  <l:icon class="icon-grey icon-md"/> ${%Skipped}
+</j:jelly>