fix: prevent forearch error

Author: Arukuen

src/plugins/global-settings/preset-controls/index.php

@@ -133,8 +133,10 @@ public function generate_css_variables_styles( $property, $presets, $prefix, $is
 
 			$presets_by_slug = [];
 			// Convert presets into an associative array with key 'slug'
-			foreach ( $presets as $preset ) {
-				$presets_by_slug[ $preset[ 'slug' ] ] = $preset;
+			if ( is_array( $presets ) ) {
+				foreach ( $presets as $preset ) {
+					$presets_by_slug[ $preset[ 'slug' ] ] = $preset;
+				}
 			}
 
 			// There is no need to generate custom presets in the editor.