`<text>` with `font-size="0px"` containing empty `<tspan>` followed by whitespaces is rendered in the wrong location

resvg version: 0.41.0

When a <text> with font-size="0px" starts with an empty <tspan> followed by whitespace, the <text> is rendered in the wrong place.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg width="300px" height="300px" version="1.1" xmlns="http://www.w3.org/2000/svg"
    xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mei="http://www.music-encoding.org/ns/mei"
    overflow="visible">
    <svg viewBox="-100 -100 400 400">
        <!-- Rendered in a wrong location -->
        <text x="40" y="80" font-size="0px">
            <tspan></tspan>
            <tspan font-size="48px">Text</tspan>
        </text>
        <!-- Rendered correctly -->
        <text x="40" y="120" font-size="0px">
            <tspan font-size="48px">Text</tspan>
            <tspan></tspan>
        </text>
        <!-- Rendered correctly -->
        <text x="40" y="160" font-size="1px">
            <tspan></tspan>
            <tspan font-size="48px">Text</tspan>
        </text>
        <!-- Rendered correctly -->
        <text x="40" y="200" font-size="0px"><tspan></tspan><tspan font-size="48px">Text</tspan></text>
        <!-- Rendered correctly -->
        <text x="40" y="240" font-size="0px">
            <tspan font-size="48px">Text</tspan>
        </text>
    </svg>
</svg>

Render result:

Start by reproducing the supplied SVG, then trace resvg's SVG text layout and positioning behavior for zero font-size text containing empty tspans and whitespace. Done means the first example renders at the intended position while the other provided cases remain correct.