Merge pull request #9318 from NuGet/addImageAllowlist

Add domain flat.badgen.net

Author: lyndaidaii

src/NuGetGallery/App_Data/Files/Content/Trusted-Image-Domains.json

@@ -23,6 +23,7 @@
         "codefactor.io",
         "coveralls.io",
         "dev.azure.com",
+        "flat.badgen.net",
         "gitlab.com",
         "img.shields.io",
         "i.imgur.com",