[JENKINS-70947] Remove Prototype $ usage from section_.js (#7955)

core/src/main/resources/lib/form/section.jelly

@@ -40,8 +40,6 @@ THE SOFTWARE.
     </st:attribute>
   </st:documentation>
 
-  <st:adjunct includes="lib.form.section_" />
-
   <f:rowSet name="${attrs.name}">
     <section class="${attrs.title!=null ? 'jenkins-section' : ''}">
       <j:if test="${attrs.title!=null}">

core/src/main/resources/lib/form/section_.js

@@ -1,77 +0,0 @@
-window.section = (function () {
-  var SectionNode = function (e) {
-    this.section = e;
-    this.children = [];
-  };
-  SectionNode.prototype = {
-    /**
-     * Points to the DIV node of the section header.
-     * @type {HTMLElement}
-     */
-    section: null,
-
-    /**
-     * Child sections.
-     *
-     * @type {Array<SectionNode>}
-     */
-    children: null,
-
-    getHTML: function () {
-      return this.section.innerHTML;
-    },
-  };
-
-  return {
-    SectionNode: SectionNode,
-    /**
-     * Builds the tree of SectionNode that represents the section hierarchy.
-     *
-     * @param {HTMLElement|string} root
-     *      The root DOM node or its ID from which we build the tree model.
-     * @return {SectionNode}
-     *      Tree structure that represents the nesting of sections.
-     *      For root node, the 'section' property refers to null.
-     */
-    buildTree: function (root) {
-      root = $(root || document.body);
-
-      /**
-       * Recursively visit elements and find all visible section headers that are not inside f:repeatable elements.
-       *
-       * @param {HTMLElement} dom
-       *      Parent element
-       * @param {SectionNode} parent
-       *      Function that returns the array to which discovered section headers and child elements are added.
-       */
-      function visitor(dom, parent) {
-        function isVisible(elem) {
-          return !!(
-            elem.offsetWidth ||
-            elem.offsetHeight ||
-            (elem.getClientRects && elem.getClientRects().length)
-          );
-        }
-
-        for (var e = dom.firstChild; e != null; e = e.nextSibling) {
-          if (e.nodeType == 1) {
-            if (e.className == "jenkins-section__title" && isVisible(e)) {
-              var child = new SectionNode(e);
-
-              parent.children.push(child);
-              // The next line seems to be unnecessary, as there are no children inside the section header itself.
-              // So this code will always returns a flat list of section headers.
-              visitor(e, child);
-            } else if (!e.classList.contains("repeated-container")) {
-              visitor(e, parent);
-            }
-          }
-        }
-      }
-
-      var top = new SectionNode(null);
-      visitor(root, top);
-      return top;
-    },
-  };
-})();