Missing config schema for Evaluation method field

Problem/Motivation

Drupal config inspector reports errors about missing schema for field.field.opigno_activity.opigno_file_upload.opigno_evaluation_method:default_value.0.value and field.field.opigno_activity.opigno_long_answer.opigno_evaluation_method:default_value.0.value elements

Proposed resolution

Provide proper schema definition for these elements