Enable Muon test with dd4hep

background information:

the Muon code in Boole crashes when using dd4hep. @farchill is working on a solution but in the meantime we need to switch it off so that we can work on the rest.

This is a follow up from !624 (merged):

• @gcorti started a discussion:

  This test fails and should not be removed.

  The Muon people are aware and working on a fix (@farchill, @desimone, @edelucia). In the meantime we should disable this test and reinstate it once we will have a fix.

Status:

Boole-Muontest with DD4hep is disabled with !626 (merged)

Need to follow:

Once the code works again we need to also reactive the test.