Crash double clicking objects with reference to non-existent filter
#### Summary:
After double-clicking to edit the content of a text, Inkscape crash. (eg. [2021-06-04](/uploads/15fd011ba2b1553c4a6b56e34012db6a/2021-06-04.gif) )
#### Steps to reproduce:
- open this SVG: [E35P13.svg](/uploads/515d5682a320cdb96aadf189f582abef/E35P13.svg) in Inkscape
- Try to edit the text of speechbubble "Did you know?"
#### What happened?
Inkscape shows a dialog "Inkscape encountered and internal error and will close now"
#### What should have happened?
The frame containing the text propose to edit the text (blinking cursor) and Inkscape not crash.
Sample attachments:
[E35P13.svg](/uploads/8b41a45fd67daf75544faa517f19dc62/E35P13.svg), edit the text of speechbubble "Did you know?"
#### Version Info:
```
- Inkscape Version: Inkscape 1.1 (1:1.1+202105261517+ce6663b3b7), PPA
- Operating System: Kubuntu
- Operating System version: 20.04.x (LTS, updated weekly)
```
issue