Remove the test equality for TransformsBase.SequentialTransform

[VEZY]

We added a method for testing equality in the tests of the package (file test-write_opf.jl) for TransformsBase.SequentialTransform:

Base.:(==)(x::TransformsBase.SequentialTransform, y::TransformsBase.SequentialTransform) = x.transforms == y.transforms

This is added because it uses === by default, which is false, but here we want to compare that the geometries of an OPF that is written and read again have the same geometry.

We should remove that when JuliaML/TransformsBase.jl#8 is fixed, because this is type piracy and it's bad. But anyway we don't export that of course.

Also, we can remove the using TransformsBase in runtests.jl, and remove the package dependency in the test project.

[VEZY]

See when JuliaML/TransformsBase.jl#9 is merged and a new version is deployed.

[VEZY]

Note: TransformsBase in the v1.5.0 right now.