fix: create multiple variants button count and status (#35915)

fix: change class for fetching columns in multiple variants
diff --git a/erpnext/stock/doctype/item/item.js b/erpnext/stock/doctype/item/item.js
index 6f1f981..31a3ecb 100644
--- a/erpnext/stock/doctype/item/item.js
+++ b/erpnext/stock/doctype/item/item.js
@@ -590,7 +590,7 @@
 			let selected_attributes = {};
 			me.multiple_variant_dialog.$wrapper.find('.form-column').each((i, col) => {
 				if(i===0) return;
-				let attribute_name = $(col).find('.control-label').html().trim();
+				let attribute_name = $(col).find('.column-label').html().trim();
 				selected_attributes[attribute_name] = [];
 				let checked_opts = $(col).find('.checkbox input');
 				checked_opts.each((i, opt) => {