reject NL objectives in MOI wrapper

[goulart-paul]

The MOI wrapper should reject objective functions that are nonlinear. I have implemented a check that will only allow models with attributes that MOI interface knows how to deal with, which implicitly rejects NLPblock etc.

Fixes the issue raised in https://github.com/orgs/osqp/discussions/706 by reporting the problem unsolvable.

Additional fix to remove regex warnings in the MOI wrapper test.

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[odow]

This might be fixed now?

[goulart-paul]

It seems like quite a few of the disabled tests are passing now. I have reenabled those that pass on my local machine. If they also pass CI checks that probably OK to bring them back.