[FIX] website_forum: use other attr than value to init select2

The backend would otherwise fail because the value has been already processed

addons/website_forum/static/src/js/website_forum.js

@@ -171,7 +171,7 @@
             // Take default tags from the input value
             initSelection: function (element, callback) {
                 var data = [];
-                _.each(JSON.parse(element.val()), function(x) {
+                _.each(element.data('init-value'), function(x) {
                     data.push({ id: x.id, text: x.name, isNew: false });
                 });
                 element.val('');
@@ -179,7 +179,6 @@
             },
         });
 
-        //TODO Remove in master
         if($('input.load_tags').length){
             var tags = $("input.load_tags").val();
             $("input.load_tags").val("");

addons/website_forum/views/website_forum.xml

@@ -376,7 +376,7 @@
             <div t-if="not is_answer">
                 <br/>
                 <input type="hidden" name="tag_type" value="select2"/>
-                <input type="hidden" name="question_tag" class="form-control col-md-9 js_select2" placeholder="Tags" t-attf-value="#{tags}"/>
+                <input type="hidden" name="question_tag" class="form-control col-md-9 js_select2" placeholder="Tags" value="see data init value" t-attf-data-init-value="#{tags}"/>
                 <br/>
             </div>
             <button class="btn btn-primary btn-lg">Save</button>