Intermediate format introduces white space in SVG while it should not

An xml:space="preserve" directive in an SVG image stored as an instream-foreign-object is not honoured. If an svg:text has an svg:tspan as a first child, that tspan will be put on the next line in the IF output no matter what, resulting into a space being added (coming from the newline between the text and the tspan) when rendering the IF into e.g., PDF.