Freeze trying to open or move file if filter is applied to a group and its children
#### Steps to reproduce:
- open Inkscape
- File > Open
- With file preview enabled (may need GTK open dialog), selecting [assets-bug-minimal.svg](https://gitlab.com/inkscape/inkscape/uploads/ed77eea8c0406937c3acd9b340219ce0/assets-bug-minimal.svg) results in a freeze and memory growth
Alternative open the file directly and try to move the group in it
```xml
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd" xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape" width="200" height="480" viewBox="0 0 200 480">
<defs>
<filter id="recursiveblur" color-interpolation-filters="sRGB" x="0" y="0" width="1" height="1">
<feGaussianBlur stdDeviation="1" in="composite1" result="blur"/>
</filter>
</defs>
<g id="base-button" filter="url(#recursiveblur)">
<g id="base-button-box" filter="url(#recursiveblur)">
<rect width="20" height="20" fill="none"/>
</g>
</g>
</svg>
```
#### What happened?
- freeze and memory growth.
- Similar to https://gitlab.com/inkscape/inkscape/-/issues/1627#note_615555995, which happens on export but requires a clip to be somewhere in the file (that bug doesn't affect this file).
#### What should have happened?
- No freeze
- Note: opening the file directly doesn't result in a freeze (i.e. running `inkscape assets-bug-minimal.svg`)
#### Debug info
- Inkscape 1.2-dev (d2b775ce59, 2021-07-05) Linux Mint 20
- Bisection says it's introduced in inkscape@11bdb7263d736f31b34877dad505b062c80c5038 so shouldn't be an issue in 1.0.2
issue