Byte order mark at the beginning of import groups file fail the process with the confusing error message

To test the fix for the BOM please conduct the following steps: 1. If you do not have a course create one (`admin/tool/generator/maketestcourse.php`). 2. In the course go to `Participants/Groups.` 3. On the bottom of the page go to `Import groups`. 4. Upload a file with BOM encoding. The simplest way to create one for me was just create it in bash (```printf '\xEF\xBB\xBF' > with_bom.txt cat source_file.txt >> with_bom.tx```). Alternatively, you can use Notepad++ and in the tap Encoding change to one of the options with BOM. The "real" content of the file should contain at least the column `groupname`. 5. Click Import groups. 6. Check if all groups are correctly uploaded and created. To test the fix for the whitespace please conduct the following steps: 1. If you do not have one create a Moodle Instance with a MySQL Database 2. If you do not have a course create one (`admin/tool/generator/maketestcourse.php`). 3. In the course go to `Participants/Groups`. 4. On the bottom of the page go to `Import groups`. 5. Upload a file with Unicode blank spaces. 6. Click Import groups. 7. Check if all groups are correctly uploaded and created.