Possibly remove Windows-bug workaround

[egpbos]

While we were working on #188, @loostrum noticed a bug in the first commit 886dbd776577bdad6a6e5abd01510acfc115cb92, which has if method == "SHAP", which should have been KernelSHAP. We fixed it in 9dc04a7343a579b331eb980b2ae59dcbe5488dbd. However, we noticed later that the SHAP test wasn't actually failing on the first commit. This lead us to suspect that maybe the manual import was no longer necessary to make tests pass on Windows. We should check this out and if indeed so remove the unnecessary import.