[FIX] website: not create editors for form field parts

Since [1] when the "Padding (Y, X)" option was added, form elements are
recognized as columns because they match the `.row > div` selector of
that new option.

This commit excludes those form elements from this option's selector.

Steps to reproduce:
- Drop a website form.
- Click on field's input.

=> An empty "Column" editor appeared in the side panel, and an error
occurred when trying to delete it.

[1]: https://github.com/odoo/odoo/commit/11418cc6f0afcc8e14869f4f38ae0d6d462ac712

task-3748574

closes odoo/odoo#157572

Signed-off-by: Benjamin Vray (bvr) <bvr@odoo.com>

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

@@ -187,6 +187,13 @@ const wSnippetMenu = weSnippetEditor.SnippetsMenu.extend({
         // "Effect" option of the "On Hover" animation option.
         const hoverEffectSelectEl = $html.find('[data-set-img-shape-hover-effect]')[0];
         delete hoverEffectSelectEl.dataset.noPreview;
+
+        // TODO remove in master: as a stable fix we exclude the form fields
+        // from the grid cell's Padding (Y, X) option.
+        const gridColumnsEl = $html.find('[data-js="GridColumns"]')[0];
+        if (gridColumnsEl) {
+            gridColumnsEl.dataset.selector = ".row:not(.s_col_no_resize) > div";
+        }
     },
     /**
      * Depending of the demand, reconfigure they gmap key or configure it

addons/website/views/snippets/snippets.xml

@@ -681,7 +681,7 @@
 
     <!-- Grid mode columns -->
     <div data-js="GridColumns"
-         data-selector=".row > div">
+         data-selector=".row:not(.s_col_no_resize) > div">
         <we-row string="Padding (Y, X)">
             <we-input data-select-style="" data-css-property="--grid-item-padding-y" data-unit="px" data-name="grid_padding_y_opt"/>
             <we-input data-select-style="" data-css-property="--grid-item-padding-x" data-unit="px" data-name="grid_padding_x_opt"/>