[FIX] website_slides: create new sections only once

Bug to reproduce
----------------

- Log in as admin
- Go to the frontend page of a course
- Click on 'Add Section'
- Fill the form (name input)
- Press 'Enter' or click on save button x times
x sections with the same name will be created

Specifications
--------------

Prevent the 'Add section' form being submitted multiple times in a row.

task-3432418

closes odoo/odoo#131107

X-original-commit: a91a60b4be5b2f606d20fbe574625b85e43407f6
Signed-off-by: Warnon Aurélien (awa) <awa@odoo.com>

addons/website_slides/static/src/js/slides_category_add.js

@@ -6,6 +6,10 @@ import { _t } from "@web/legacy/js/services/core";
 
 var CategoryAddDialog = Dialog.extend({
     template: 'slides.category.add',
+    events: Object.assign(
+        { "submit form#slide_category_add_form": "_onClickFormSubmit" },
+        Dialog.events
+    ),
 
     /**
      * @override
@@ -16,8 +20,8 @@ var CategoryAddDialog = Dialog.extend({
             size: 'medium',
             buttons: [{
                 text: _t('Save'),
-                classes: 'btn-primary',
-                click: this._onClickFormSubmit.bind(this)
+                classes: 'btn-primary o_js_website_slides_add_category_btn',
+                click: this._onClickFormSubmit.bind(this),
             }, {
                 text: _t('Back'),
                 close: true
@@ -37,10 +41,24 @@ var CategoryAddDialog = Dialog.extend({
         return $form[0].checkValidity();
     },
 
+    //--------------------------------------------------------------------------
+    // Handlers
+    //--------------------------------------------------------------------------
+
+    /**
+     * Handle form submission on click button or press ENTER key. Prevent multiple submissions
+     * @private
+     * @param {Event} ev
+     */
     _onClickFormSubmit: function (ev) {
-        var $form = this.$('#slide_category_add_form');
-        if (this._formValidate($form)) {
-            $form.submit();
+        ev.preventDefault();
+        const form = document.getElementById("slide_category_add_form");
+        if (!form.classList.contains("o_js_website_slides_form_submitted")) {
+            if (this._formValidate($(form))) {
+                form.classList.add("o_js_website_slides_form_submitted");
+                document.querySelector("button.o_js_website_slides_add_category_btn").disabled = true;
+                form.submit();
+            }
         }
     },
 });