chore: add model-exts conversion check

[ferbetanzo]

Now that we are able to import models in python (#2581) we can enable the roundtrip checks in the validate fixture of the hugr-py tests.

I have also added a couple more models to check when writing, mainly JSON with compression and BINARY with no compression. This adds around 5 seconds of running time to the hugr-py tests.

And I've separated the test_envelope.py::test_envelope test case into test_envelope_binary (parametrized for each EnvelopeFormat and compression) and test_envelope_text.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.02%. Comparing base (f3cfff4) to head (42282be).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2613      +/-   ##
==========================================
- Coverage   83.71%   83.02%   -0.70%     
==========================================
  Files         261      256       -5     
  Lines       52631    48158    -4473     
  Branches    47372    42899    -4473     
==========================================
- Hits        44058    39981    -4077     
+ Misses       6183     6133      -50     
+ Partials     2390     2044     -346     

Flag	Coverage Δ
python	88.85% <ø> (ø)

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[mark-koch]

Looks like the compressed ones you added are not included in hugr convert --format? Could you update this comment accordingly?

[ferbetanzo]

Modified the comments to add some more clarity.

[mark-koch]

Thanks!