[FA-55] Finished aside from deactivation/integration events

FictionArchive.Service.UserService/GraphQL/Mutation.cs

@@ -17,7 +17,7 @@ public class Mutation
         ClaimsPrincipal claimsPrincipal)
     {
         // Get the current user's OAuth provider ID from claims
-        var oAuthProviderId = claimsPrincipal.FindFirst("sub")?.Value;
+        var oAuthProviderId = claimsPrincipal.FindFirst(ClaimTypes.NameIdentifier)?.Value;
         if (string.IsNullOrEmpty(oAuthProviderId))
         {
             throw new InvalidOperationException("Unable to determine current user identity");