Note editor - discard invalid value in note

[xkopenreview]

when invitation is modified after some notes were posted, the value in those notes may become invalid. for example invitation field type is changed from string to string[] but the value in note is still string
currently this may cause the note editor logic to break

discussed this with Carlos:

1. user who edited this change should be notified that the change could make value in some notes invalid
2. note editor should discard value in note when there's a type mismatch or value mismatch (for example the note value is not in options defined in invitation) but still show it for user to reference (because user need to input new value)