Ext.net.FieldNote.setNote() error if no initial note is set

[fabriciomurta]

Found: 5.2.0. Ext.NET forum thread: setNote fails when no note is originally set

The Ext.net.FieldNote.setNote() method references null/undefined me.noteEl if called when a field is defined with no Note="value" (client-side note: "value") at define time.

When the method is called, if there's no fieldNote element, it should be created the same way it is when defining the field with a note.

This is an Ext.NET-specific feature, so this issue should not be tagged after the Sencha label, although changes in how Ext JS works reintroduced this issue, initially fixed at #1621.