[admin] Translate error message when missing "вид" when creating new document.

[Tuscann]

Which area(s) of Podkrepi.bg are affected?

Desktop layout

Describe the Bug

Translate error message to Bulgarian.

To Reproduce

1. Open https://dev.podkrepi.bg/admin/documents/create with admin user
2. Add name : "dddddd"
   Add name of file: "dasdasd"
   Add type of file : "#$$"
   Add description: "dasdas"
   Add link "dasd"
3. Click button "Изпрати"
4. Check red error under "Вид"

Expected Behavior

Translate to Bulgarian "type must be one of the following values: invoice, receipt, medical_record, other"

Which browser are you using? (if relevant)

Vivaldi