Fix erroneous `////` in default URL for blazorwasm --aad-b2c-instance parameter#63829

Copilot wants to merge 2 commits intomaindotnet/aspnetcore:mainfrom

copilot/fix-1d6b20d0-a0f4-4176-952e-e1f40b1c8213dotnet/aspnetcore:copilot/fix-1d6b20d0-a0f4-4176-952e-e1f40b1c8213Copy head branch name to clipboard