fix: use Self return type for Model.__from_data__

[dflorenzano]

• change return type to use Self in Model.from_data to enable subclasses to retain their type when deserialized.
• used typing_extensions instead of typing to preserve python 3.9 compatibility.

What type of change is this?

• Bug fix in a backwards-compatible manner.
• New feature in a backwards-compatible manner.
• Breaking change: bug fix or new feature that involve incompatible API changes.
• Other (e.g. doc update, configuration, etc)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I added a line to the CHANGELOG.md file in the Unreleased section under the most fitting heading (e.g. Added, Changed, Removed).
• I ran all tests on my computer and it's all green (i.e. invoke test).
• I ran lint on my computer and there are no errors (i.e. invoke lint).
• I added new functions/classes and made them available on a second-level import, e.g. compas.datastructures.Mesh.
• I have added tests that prove my fix is effective or that my feature works.
• I have added necessary documentation (if appropriate)

[tomvanmele]

i think the tests are wrong

[tomvanmele]

same here. i don't think you are testing the behaviour you intend to test

[dflorenzano]

Added the other test, the two failure modes are separate, so i still kept it, should i directly cancel it?