Use 'editor.import.fileFiledName', 'editor.upload.image.fileFiledName', 'editor.upload.video.fileFiledName' and 'editor.upload.file.fileFiledName' keys to set fieldName for formData in upload and import.

{ 
    'editor.import.fileFieldName': 'file',
    'editor.upload.image.fileFieldName': 'file',
    'editor.upload.video.fileFieldName': 'file',
    'editor.upload.file.fileFieldName': 'file'
}