Reopened diagrams in PNG don't remember background value used during export

[pktiuk]

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• [X] I agree to follow the Code of Conduct that this project adheres to.
• [X] I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Describe the bug

In case of editing existing .png files (with embedded diagram metadata) overwriting it causes overwriting earlier selected value of Zoom

To Reproduce

1. Create diagram
2. Export it to PNG (File->Export as...-> PNG...) with non-transparent background and with metadata
3. Close app
4. Check the image
5. Open app
6. Open file (File->Open)
7. Change something
8. Save (Ctrl+S)
9. Check image background

Expected behavior

Image should have the same background transparency

Screenshots If applicable, add screenshots to help explain your problem.

draw.io version (In the Help->About menu of the draw.io editor): v23.0.3 (Flatpak package)

Desktop (please complete the following information):

• OS: [e.g. iOS] Linux Pop!_OS 22.04
• Browser [e.g. chrome, safari]
• Browser Version [e.g. 22]

I tested the problem in incognito/private mode with all browser extensions switched off, write "yes" below:

Additional context

This is very similar issue to https://github.com/jgraph/drawio/issues/4125

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[pktiuk]

Issue still exists