Alternate Marketplace URL Not working with product.json

[balajib-b]

Does this issue occur when all extensions are disabled?: No

• VS Code Version: 1.67.1
• OS Version: Ubuntu 20.04
  Steps to Reproduce:

1. Change Marketplace URL to microsoft marketplace for testing

2. From this - "extensionsGallery": {
   "serviceUrl": "https://open-vsx.org/vscode/gallery",
   "itemUrl": "https://open-vsx.org/vscode/item",
   "resourceUrlTemplate": "https://open-vsx.org/vscode/asset/{publisher}/{name}/{version}/Microsoft.VisualStudio.Code.WebResources/{path}",
   "controlUrl": "",
   "recommendationsUrl": ""
   },

3. To this - "extensionsGallery": {
   "serviceUrl": "https://marketplace.visualstudio.com/_apis/public/gallery",
   "cacheUrl": "https://vscode.blob.core.windows.net/gallery/index",
   "itemUrl": "https://marketplace.visualstudio.com/items"
   },

4. Marketplace is still openvsx.org