Excel mime types not working correctly

[peterostrander]

Adding validation for MS Excel spreadsheet mime types doesn't appear to be working correctly:

data-validation-allowing="application/vnd.ms-excel, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"

The above attr allows for non spreadsheet MS documents like ppt and pptx to be pass validation. The error output when uploading a non-compatible file (like a png) returns the following:

Only files of type application/vnd.ms, excel, application/vnd.openxmlformats, officedocument.spreadsheetml.sheet is allowed

It appears there's some issue when parsing mime types that contain a dash.