[CATALYST-1815] Include screenshot of new feature for Catalyst 1.6.0 (#1286)

<!-- Ticket number or summary of work -->
# [CATALYST-1815]

## What changed?
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* Added missing screenshot of new feature


[CATALYST-1815]:
https://bigcommercecloud.atlassian.net/browse/CATALYST-1815?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: jorgemoya

docs/storefront/catalyst/release-notes/1-6-0.mdx

@@ -8,6 +8,12 @@ For additional details, you can refer to the [Catalyst 1.6 changeset](https://gi
 
 Catalyst now supports reCAPTCHA v2 on the registration, contact us, and product review forms. When reCAPTCHA is enabled in the BigCommerce admin, a reCAPTCHA widget is rendered on each supported form. Validation is performed server-side in the corresponding form actions — the token is read from the native `g-recaptcha-response` field that the reCAPTCHA widget injects into the form, so no manual client-side token extraction is required.
 
+<img
+  src="https://storage.googleapis.com/bigcommerce-production-dev-center/images/catalyst/release-notes/1-6-0/screencapture-catalyst-demo-site-register-2026-03-18-10_35_53.png"
+  alt="Registration form with reCaptcha support"
+  className="rounded-xl mt-2"
+/>
+
 ### Migration
 
 1. Install the required dependencies: