Fix SNS_Optimal Velocity Solver to pass tests

The failing test is inside: `sns_ik_lib/test/sns_ik_vel_test.cpp`:
```
TEST(sns_ik, vel_ik_SNS_Optimal_test) {
   runSnsVelkTest(23539, sns_ik::VelocitySolveType::SNS_Optimal); }
```
This test should be commented out for now, to allow for CI testing. Longer term, we need to figure out what the issue is with the SNS Optimal solver.