It looks like the process of uploading is breaking the file, somehow. You can run a diff on the original I found on wikipedia: https://upload.wikimedia.org/wikipedia/en/d/d2/Stitch_(Lilo_%26_Stitch).svg
Doing so, it looks like removing linebreaks somehow busted this? The data appears the same, but everything has been moved to a single line rather than being multi-line? Can anyone verify my analysis is correct here?
In testing this idea, copied a simple SVG created with GraphViz on Windows that contained CR (Carriage Return) and LF (Line Feed) and tried an upload. Received the error dialog:
Sorry, but we couldn’t determine the size of the image. Maybe your image is corrupted?
Then using a text editor (NotePad++) used the menu option
View -> Show Symbol -> Show All Characters to see the line end characters; they were CR/LF. Changed them to LF, saved the file and uploaded.