fix(WooCommerce): always expect signature in webhook requests (#28367)

diff --git a/erpnext/erpnext_integrations/connectors/woocommerce_connection.py b/erpnext/erpnext_integrations/connectors/woocommerce_connection.py
index f5f9ce3..9409485 100644
--- a/erpnext/erpnext_integrations/connectors/woocommerce_connection.py
+++ b/erpnext/erpnext_integrations/connectors/woocommerce_connection.py
@@ -19,8 +19,7 @@
 	)
 
 	if frappe.request.data and \
-		frappe.get_request_header("X-Wc-Webhook-Signature") and \
-		not sig == bytes(frappe.get_request_header("X-Wc-Webhook-Signature").encode()):
+		not sig == frappe.get_request_header("X-Wc-Webhook-Signature", "").encode():
 			frappe.throw(_("Unverified Webhook Data"))
 	frappe.set_user(woocommerce_settings.creation_user)