💡 handle case where user has no additional data

This isn't necessarily a bug as the code was working as intended... Why some users don't have Additional Data needs to be explored further.

Author: JoshuaTheMiller

source/Gttsb.Gh/ActiveDirectoryFacade.cs

@@ -41,6 +41,17 @@ public async Task<MembersResponse> FetchMembersAsync(string groupDisplayName)
             Func<User, Member> memberToUser = (User m) => {
                 // TODO: handle exception case?
 
+                if(m.AdditionalData == null)
+                {
+                    return new Member
+                    (
+                        DisplayName: m.DisplayName,
+                        Email: m.Mail,
+                        Id: m.Id,
+                        PotentialGitHubId: string.Empty
+                    );
+                }
+
                 if(m.AdditionalData.TryGetValue(filteredExtensionName, out var gitHubId))
                 {                    
                     return new Member