Uploading 2 files with the same extension, but different case, does not work.

Overview: When uploading multiple files to Data Import at the same time, we disallow upload of different file types, based on their file extensions. Thus I cannot upload a .jpg and a .mrc file at the same time, but I should be able to upload multiple .mrc files at the same time. FOLIO allows the upload of 2 .mrc files at the same time, but does not allow the upload of a .mrc and .MRC file at the same time. It should be ignoring the case of the file extension.

Steps to Reproduce:

1. Log into FOLIO-snapshot as diku_admin
2. Go to Data Import landing page
3. Upload 2 MARC files at the same time, one with file extension .mrc and one with file extension .MRC (sample files attached to this ticket)

Expected Results: Both files should be uploaded, regardless of the case of the file extension

Actual Results: I get the inconsistent file extensions message that disallows upload

Additional Information: See attached files and screenshot