[FIX] web_editor, website: improve grid image code

Commit [1] added the support for images with a link set on them in grid
mode.

As a follow up, this commit does the following:
- Removes the `!important` from the grid image anchor CSS rules, as they
were not really needed.
- Checks if the image has a closest `o_grid_item_image` column instead
of checking the parent in the `GridImage` options. Indeed, this class
already guarantees that the image is well a grid image; we can therefore
simplify the code.

It also removes a comment that was forgotten in commit [2].

[1]: https://github.com/odoo/odoo/commit/085d70cea571ea80c141ac6005e8bd8333bd269f
[2]: https://github.com/odoo/odoo/commit/d8c374e3e6b31bf88aa42952aadf3379936f7600

related to opw-3580128

closes odoo/odoo#149681

X-original-commit: 9244e85ebb9e1605292698fe31ad94da7709ab86
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

addons/web_editor/static/src/js/common/grid_layout_utils.js

@@ -326,8 +326,7 @@ export function _checkIfImageColumn(columnEl) {
 }
 /**
  * Removes the line breaks and textnodes of the column, adds the grid class and
- * sets the image width to default so it can be displayed as expected. Also
- * blocks the edition of the column.
+ * sets the image width to default so it can be displayed as expected.
  *
  * @private
  * @param {Element} columnEl a column containing only an image.

addons/web_editor/static/src/scss/web_editor.frontend.scss

@@ -99,8 +99,8 @@
 
         // Needed when "a" is "display: block".
         > a {
-            width: 100% !important;
-            height: 100% !important;
+            width: 100%;
+            height: 100%;
         }
     }
 }

addons/website/static/src/js/editor/snippets.options.js

@@ -4029,15 +4029,7 @@ options.registry.GridImage = options.Class.extend({
      * @returns {?HTMLElement}
      */
     _getImageGridItem() {
-        let parentEl = this.$target[0].parentNode;
-        if (parentEl.matches("a")) {
-            // Case of an image link.
-            parentEl = parentEl.parentNode;
-        }
-        if (parentEl && parentEl.classList.contains('o_grid_item_image')) {
-            return parentEl;
-        }
-        return null;
+        return this.$target[0].closest(".o_grid_item_image");
     },
     /**
      * @override