When using the export tool, one can upload a text file of biblionumbers. We should trim spaces from that file, if there are any, because otherwise it breaks. There are other places where we allow similar uploads (like inventory) and those should also get trimmed, but maybe not all in one bug.
We probably need to be a bit careful when trimming, as whitespace can also be used as a separator in some places (see BarcodeSeparators system preference)