Remove azure canvas backend

closes #25833

Issue description: Now that the raqote backend has reached feature parity and been enabled by default, we should remove the unused azure backend entirely.

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- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [x] These changes fix #25833

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because PR only removes code, doesn't add new code