Fix race condition in ChillCollectionType

In some dcase, the collection is not initialized when a showHide is launched before the collection is fully initialized.

src/Bundle/ChillMainBundle/Resources/views/Form/fields.html.twig

@@ -163,6 +163,7 @@
     <div class="chill-collection">
         <ul class="list-entry"
             {{ form.vars.js_caller }}="{{ form.vars.js_caller }}"
+            data-uniqid="{{ form.vars.uniqid|escape('html_attr') }}"
             data-collection-name="{{ form.vars.name|escape('html_attr') }}"
             data-collection-identifier="{{ form.vars.identifier|escape('html_attr') }}"
             data-collection-button-remove-label="{{ form.vars.button_remove_label|trans|e }}"
@@ -184,6 +185,8 @@
 
         {% if form.vars.allow_add == 1 %}
         <button class="add-entry btn btn-misc"
+            type="button"
+            data-uniqid="{{ form.vars.uniqid|escape('html_attr') }}"
             data-collection-add-target="{{ form.vars.name|escape('html_attr') }}"
             data-form-prototype="{{ ('<div>' ~ form_widget(form.vars.prototype) ~ '</div>')|escape('html_attr') }}" >
             <i class="fa fa-plus fa-fw"></i>