Bug 1919297: Clean up unused isProductURL import in browser.js. r=shopping-reviewers,Gijs

Differential Revision: https://phabricator.services.mozilla.com/D222477

browser/base/content/browser.js

@@ -39,7 +39,6 @@ ChromeUtils.defineESModuleGetters(this, {
   E10SUtils: "resource://gre/modules/E10SUtils.sys.mjs",
   ExtensionsUI: "resource:///modules/ExtensionsUI.sys.mjs",
   HomePage: "resource:///modules/HomePage.sys.mjs",
-  isProductURL: "chrome://global/content/shopping/ShoppingProduct.mjs",
   LightweightThemeConsumer:
     "resource://gre/modules/LightweightThemeConsumer.sys.mjs",
   LoginHelper: "resource://gre/modules/LoginHelper.sys.mjs",

browser/base/content/browser.js.globals

@@ -128,7 +128,6 @@
   "E10SUtils",
   "ExtensionsUI",
   "HomePage",
-  "isProductURL",
   "LightweightThemeConsumer",
   "LoginHelper",
   "LoginManagerParent",