[FIX] web_editor: prevent deleting carousel-item with the delete button

Indeed, the carousel-item elements are linked to other DOM (like
indicators) and removing one would imply enabling another one... all of
this is handled by the carousel "remove slide" option.

Note: the UI to add and remove slides will be refactored in a future
update of this future saas anyway.

Part of https://github.com/odoo/odoo/pull/38997
task-2090180

closes odoo/odoo#38997

Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>

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

@@ -97,7 +97,7 @@ var SnippetEditor = Widget.extend({
             $customize.find('.oe_snippet_clone').addClass('d-none');
         }
 
-        if (!this.isTargetParentEditable) {
+        if (!this.isTargetParentEditable || this.$target.is('.carousel-item')) { // TODO get rid of the carousel-item hack somehow
             $customize.find('.oe_snippet_remove').addClass('d-none');
         }