[BUG] JMP & GCP crashing when using "Threads" parallel profile

[RobSalati]

Describe the bug
When you set the Matlab parallel profile to multithreading, JMP and GCP crash while making calls to OpenSim functions.
JMP exits with error message:

Error using Model
Unable to resolve the name 'org.opensim.modeling.Model'.

Error in computeInnerOptimization (line 37)
model = Model(modelFile);
....

GCP exits with error message:
Error using Model
Unable to resolve the name 'org.opensim.modeling.Model'.

Error in calcGroundContactPersonalizationTaskCost (line 38)
models.("model_" + foot) = Model(inputs.surfaces{foot}.model);
....

To Reproduce

1. Go to Parallel Computing Toolbox Preferences.
2. Set Default Profile to Threads.
3. Execute either RunJMP.m or runGCP.m in nmsm-tutorial folder.

Expected behavior
JMP and GCP should run without crashing.

Desktop (please complete the following information):

• OS: Windows
• OpenSim Version: 4,4
• MATLAB Version: 2023a
• NMSM Pipeline Version: v1.0

Additional context
This error only occurs when the parallel profile is set to threads. I have run JMP and GCP with multiprocessing with no issues.

[SpencerTWilliams]

I think this documentation explains the issue. Based on how some of our old mex files are written, I don't think Matlab's thread-based parallel processing will support the OpenSim API. We probably don't have a way of changing this, so we should warn users in our documentation not to switch to the thread-based mode.