Do not validate for unevaluatedProperties

[ikonst]

It appears that without checking is_valid the test suite still passes. The invalid properties already produce an error, so that the "unevaluated property" error is never needed to achieve a validation failure. On the contrary, when all property validation succeeds, "unevaluated property" could still produce an error.

Arguably, producing an error for expected but invalid properties is also confusing, being a "double jeopardy" of validation failures.

---

📚 Documentation preview 📚: https://python-jsonschema--1075.org.readthedocs.build/en/1075/

[Julian]

Nice! Indeed looks like this is a decent (~40%) speedup for the (unevaluatedProperties-specific) microbenchmark that I've been referring to for the new release.

Obviously I can believe there's gaps in the precise output for unevaluatedProperties (especially given the spec ambiguities), so this is potentially in need of revisiting later when unevaluatedProperties gets another look, but certainly seems like a win for now. Well done, merging.