Fix: 404 error for No results block CSS file (#11854)

This commit introduces the `get_block_type_style` method in the `ProductCollectionNoResults` class. This new method is designed to manage frontend style handling specifically for this block type. Currently, it returns null, indicating no specific styles are assigned at this stage.

src/BlockTypes/ProductCollectionNoResults.php

@@ -58,6 +58,15 @@ protected function get_block_type_script( $key = null ) {
 		return null;
 	}
 
+	/**
+	 * Get the frontend style handle for this block type.
+	 *
+	 * @return null
+	 */
+	protected function get_block_type_style() {
+		return null;
+	}
+
 	/**
 	 * Set the URL attributes for "clearing any filters" and "Store's home" links.
 	 *