Elsa server crashes if an unmanaged dll is placed into the DropIns folder

I have a custom activity that acts as a wrapper around an unmanaged dll.
To invoke methods from the dll, I use DllImport. For simplicity reasons, I would expect to be able to place both the managed and unmanaged dll into the same directory. Doing so leads to the server crashing.

I installed the DropIns in Programm.cs with
```cs
elsa.InstallDropIns(options =>
options.DropInRootDirectory = Path.Combine(Directory.GetCurrentDirectory(), "App_Data", "Plugins"));
```

The server crashes at this line with the error `System.BadImageFormatException: 'PE image does not have metadata.'`

I would expect the server to load all DropIns that can be loaded and ignore unmanaged dlls.
I would at least expect the server to not crash on a dll that can't be loaded.