Count the number of items selected for any multi-select picklist field.
- Create a multi-select picklist field on the Account object and add 5 choices to it.
- Create a 'Counter' number field.
- Automatically populate 'Counter' with the number of picklist items chosen.
- Make sure 'Counter' resets to 0 when all picklist items are removed.
- Test class with 100% code coverage.