fix: update the filter removing existing users from Jellyfin import modal (#924)

Currently import button sometimes shows already imported users and this would break it if an admin
tries to import an already imported user.

src/components/UserList/JellyfinImportModal.tsx

@@ -56,14 +56,6 @@ const JellyfinImportModal: React.FC<JellyfinImportProps> = ({
     `/api/v1/user?take=${children}`
   );
 
-  data?.forEach((user, pos) => {
-    if (
-      existingUsers?.results.some((data) => data.jellyfinUserId === user.id)
-    ) {
-      data?.splice(pos, 1);
-    }
-  });
-
   const importUsers = async () => {
     setImporting(true);
 
@@ -209,7 +201,14 @@ const JellyfinImportModal: React.FC<JellyfinImportProps> = ({
                       </tr>
                     </thead>
                     <tbody className="divide-y divide-gray-700 bg-gray-600">
-                      {data?.map((user) => (
+                      {data
+                        ?.filter(
+                          (user) =>
+                            !existingUsers?.results.some(
+                              (u) => u.jellyfinUserId === user.id
+                            )
+                        )
+                        .map((user) => (
                           <tr key={`user-${user.id}`}>
                             <td className="whitespace-nowrap px-4 py-4 text-sm font-medium leading-5 text-gray-100">
                               <span