[FIX] website: only stop clone's animations on cloning

/!\ Should not be forward-ported ! As further explained, this commit is
/!\ only partial backports of 12.0 commits. All conflicts should be
/!\ ignored.

A recently merged PR https://github.com/odoo/odoo/pull/35029 was in
fact developed for 12.0 originally and finally merged in 11.0 to solve
potential same bugs. The problem is that one line of that merge relied
on a 12.0 feature that is missing in 11.0: the ability to stop
animations *on part of the DOM only*.

This commit chose to backport that 12.0 feature instead of retargeting
the original PR as it will be needed for another unrelated fixes. So,
this commit partially backport those commits:
- https://github.com/odoo/odoo/commit/0a31cb9b4ae461119ecafdd05c5b979621ffb039
- https://github.com/odoo/odoo/commit/b56e647f2c540d34860cdee8a6adf0785ce3b8ef

(Only the stop animation ability part, not the way it was used).

Note that the first commit was already partially backported with
https://github.com/odoo/odoo/commit/59e1bdff221f4a099f6000eb9884f84f772c38bb

closes odoo/odoo#35230

Signed-off-by: Romain Derie (rde) <rde@odoo.com>

addons/website/static/src/js/content/website_root.js

@@ -166,12 +166,21 @@ var WebsiteRoot = BodyManager.extend({
      * in edition mode for example.
      *
      * @private
+     * @param {jQuery} [$from]
+     *        only stop the animations linked to the given element(s) or one of
+     *        its descendants
      */
-    _stopAnimations: function () {
-        _.each(this.animations, function (animation) {
-            animation.destroy();
+    _stopAnimations: function ($from) {
+        var removedAnimations = _.map(this.animations, function (animation) {
+            if (!$from
+             || $from.filter(animation.el).length
+             || $from.find(animation.el).length) {
+                animation.destroy();
+                return animation;
+            }
+            return null;
         });
-        this.animations = [];
+        this.animations = _.difference(this.animations, removedAnimations);
     },
 
     //--------------------------------------------------------------------------
@@ -195,9 +204,10 @@ var WebsiteRoot = BodyManager.extend({
      * stopped.
      *
      * @private
+     * @param {OdooEvent} ev
      */
-    _onAnimationStopDemand: function () {
-        this._stopAnimations();
+    _onAnimationStopDemand: function (ev) {
+        this._stopAnimations(ev.data.$target);
     },
     /**
      * @todo review