Auto merge of servo#28601 - yvt:patch-1, r=KiChjang

Delete `canvas.png`

This PR deletes `:/canvas.png`, which was presumably accidentally added by commit 5f91ab0.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #___ (GitHub issue number if applicable)

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because this file is used absolutely nowhere

Author: bors-servo