nextcloud/user_run: block new setups when any folder is already configured

Set _nc_first=0 in the already-found branch so that a configured folder
prevents subsequent entries from wiping the Nextcloud config.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client_software/0050_nextcloud_desktopclient/user_run.sh

@@ -92,6 +92,7 @@ for CLIENT_DATA_DECLARE_LINE in "${CLIENT_DATA_SYNC[@]}"; do
     # Now, CLIENT_DATA_SYNC_LINE[0] contains the local path and CLIENT_DATA_SYNC_LINE[1] contains the remote path
     if grep -q "localPath=${CLIENT_DATA_SYNC_LINE[0]}" "/${HOME}/.var/app/com.nextcloud.desktopclient.nextcloud/config/Nextcloud/nextcloud.cfg"; then
         echo "Already found configured local folder ${CLIENT_DATA_SYNC_LINE[0]} syncing with ${CLIENT_DATA_SYNC_LINE[1]} . Leaving it unchanged."
+        _nc_first=0
     else
         echo "Setup new sync from remote ${CLIENT_DATA_SYNC_LINE[1]} to local ${CLIENT_DATA_SYNC_LINE[0]}"
         if [ "${_nc_first}" -eq 0 ]; then