Update release notes

Author: itsmeichigo

RELEASE-NOTES.txt

@@ -4,6 +4,7 @@
 23.3
 -----
 - [*] Order details: Display only physical items in the Shipping Labels section. [https://github.com/woocommerce/woocommerce-ios/pull/16127]
+- [*] Product form: Display user-friendly error message when saving duplicated GTIN/UPC/EAN/ISBN. [https://github.com/woocommerce/woocommerce-ios/pull/16146]
 - [internal] Address deprecated view modifiers usage following iOS17 API updates [https://github.com/woocommerce/woocommerce-ios/pull/16080]
 - [internal] POS Modularization: Removed direct ServiceLocator usage within POS by requiring complex Woo app target dependencies to be injected via POS dependency protocols, and moved reusable dependencies to WooFoundation and Yosemite [https://github.com/woocommerce/woocommerce-ios/pull/16132]