Known plates can end up with a literal 'null' in the Notes field

Steps to reproduce:

• Create a new known plate filling in the plate (e.g. TEST123) and the name (Test Car), leave the note BLANK.

• Save it

• Go back to edit the same plate.

• Change the name to something different (Test Truck), don’t go to the note field.

• Save it

• Navigate to another tab and back to refresh the list.

• You’ll see the word ‘null’ in the Notes field.