remove required parameter for ext_expires_on (#1366)
remove required parameter for ext_expires_on (#1366)


AzureAD/microsoft-authentication-library-for-dotnet,AzureAD/microsoft-authentication-library-for-dotnet,AzureAD/microsoft-authentication-library-for-dotnet,AzureAD/microsoft-authentication-library-for-dotnet,AzureAD/azure-activedirectory-library-for-dotnet