[bug] CSV import: failure on importing UTF16 encoded CSV files fails with 500 internal server error

[nemesifier]

Describe the bug
Only files encoded with UTF8 without BOM marker are accepted now, but trying to upload UTF16 fails with an exception that doesn't point out this issue.

Steps To Reproduce
Create batch import using CSV, try these select files:

• import-bug-utf16.csv
• Eap G720 accountstest.csv

Expected behavior
A clear error message or handling the encoding automatically.

Screenshots