Remove inferred test for EAGO.Optimizer

[odow]

We recently moved the MOI interface of Ipopt to a package extension (because many people wanted to use Ipopt but not MOI, and it's a fairly hefty dependency for them to carry around and compile).

The downside is that Ipopt.Optimizer is no longer type stable: https://github.com/jump-dev/Ipopt.jl?tab=readme-ov-file#type-stability

This shows up in your default EAGO.Optimizer constructor, which is now also not type stable.

We have two options:

• Remove this test
• Change the compat to Ipopt = "1.10" and use the type-stable constructor IpoptMathOptInterfaceExt.Optimizer.

I went for the former. I can make a PR for the latter if you'd prefer.

[DimitriAlston]

Thanks for the bringing this up. Long term it's probably better to use the new type-stable constructor everywhere, so I made #146 based on the latter approach.