Layout message icons

Closes #3143237

core/themes/claro/css/theme/layout-builder.css

+/*
+ * DO NOT EDIT THIS FILE.
+ * See the following change record for more information,
+ * https://www.drupal.org/node/3084859
+ * @preserve
+ */
+
+/**
+ * @file
+ * Overriding styles from the Layout Builder module.
+ */
+
+.layout-builder__message--defaults .messages,
+.layout-builder__message--overrides .messages {
+  background-position: 1.25rem 1.625rem; /* LTR */
+}
+
+[dir="rtl"] .layout-builder__message--defaults .messages,
+[dir="rtl"] .layout-builder__message--overrides .messages {
+  background-position: right 1.25rem top 1.625rem;
+}
+
+.layout-builder__message--defaults .messages__header,
+.layout-builder__message--overrides .messages__header {
+  background: none;
+}