Only check NLPBlock support if needed

[blegat]

If there are no NLP part, Pavito should allow, e.g. QP or QCP solvers too

[codecov]

Codecov Report

Merging #36 into master will not change coverage.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##           master      #36   +/-   ##
=======================================
  Coverage   67.65%   67.65%           
=======================================
  Files           4        4           
  Lines         504      504           
=======================================
  Hits          341      341           
  Misses        163      163           

Impacted Files	Coverage Δ
src/MOI_wrapper.jl	77.85% <50.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3a087d4...4ad02bc. Read the comment docs.