new test expects shorter term names

[turbomam]

• python test for term name length #736

[turbomam]

This PR errors out as expected ecause there are two terms with names over 20 characters:

poetry run python -m unittest discover
.INFO:root:Importing linkml:types as /home/runner/.cache/pypoetry/virtualenvs/mixs-VD9cwaNk-py3.10/lib/python3.10/site-packages/linkml_runtime/linkml_model/model/schema/types from source /home/runner/work/mixs/mixs/tests/../src/mixs/schema/mixs.yaml; base_dir=None
F
======================================================================
FAIL: test_term_name_length (tests.test_term_name_length.TestTermNameLength)
Test term name length.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/mixs/mixs/tests/test_term_name_length.py", line 36, in test_term_name_length
    self.assertDictEqual(slot_name_length_too_long, {},
AssertionError: {'nose_mouth_teeth_throat_disord': 30, 'x16s_recover_software': 21} != {}
- {'nose_mouth_teeth_throat_disord': 30, 'x16s_recover_software': 21}
+ {} : Slots whose names are greater than [20](https://github.com/GenomicsStandardsConsortium/mixs/actions/runs/7387536437/job/20096442275#step:7:21) characters: {'nose_mouth_teeth_throat_disord': 30, 'x16s_recover_software': [21](https://github.com/GenomicsStandardsConsortium/mixs/actions/runs/7387536437/job/20096442275#step:7:22)}

----------------------------------------------------------------------
Ran 2 tests in 2.661s

FAILED (failures=1)


make: *** [Makefile:1[22](https://github.com/GenomicsStandardsConsortium/mixs/actions/runs/7387536437/job/20096442275#step:7:23): test-python] Error 1
Error: Process completed with exit code 2.

[turbomam]

Action item: rename

{'nose_mouth_teeth_throat_disord': 30, 'x16s_recover_software': 21}