refactor: enhance GSTIN validation error messages

(cherry picked from commit 8969581)

Author: Abdeali099

india_compliance/public/js/utils.js

@@ -268,20 +268,30 @@ Object.assign(india_compliance, {
     },
 
     validate_gstin(gstin, show_msg = true) {
+        const opts = { title: __("Error"), indicator: "red" };
+
         if (!gstin || gstin.length !== 15) {
-            if (show_msg) frappe.msgprint(__("GSTIN must be 15 characters long"));
+            if (show_msg) {
+                frappe.msgprint({
+                    message: __("GSTIN must be 15 characters long"),
+                    ...opts,
+                });
+            }
+
             return;
         }
 
         gstin = gstin.trim().toUpperCase();
 
         if (GSTIN_REGEX.test(gstin) && is_gstin_check_digit_valid(gstin)) {
             return gstin;
-        } else {
-            if (show_msg) frappe.msgprint(__("Invalid GSTIN"));
+        } else if (show_msg) {
+            frappe.msgprint({
+                message: __("Invalid GSTIN"),
+                ...opts,
+            });
         }
     },
-
     guess_gst_category(gstin, country) {
         if (!gstin) {
             if (country && country !== "India") return "Overseas";