Advanced mode ground file selection options

[GH-MostowyJ]

Hello! I think I found a bug that causes the INIBuilder to skip the prompt for the file selection options (["PREVIOUS STEP", "Enter path manually", "Use filepicker"]) when selecting a ground file. On Line 71 in INIBuilder/run.jl, the list of file selection options is assigned to "n" instead of the radio menu request term:

71 n = ["PREVIOUS STEP", "Enter path manually", "Use filepicker"]
72 n == 1 && step3()

This seems to cause it to skip asking for a file selection option and go straight into the filepicker. When swap Line 71 for:

71 n = request(RadioMenu(opt))

the file selection options appear and function as expected.

[vlandau]

@ranjanan does this make sense to you? If so, @GH-MostowyJ maybe you could put in a PR with this change?