form.field.Text: add a trim() logic for submitting values

@linchen, @ThorstenRaab: i had to revert your idea for a fix: https://github.com/neomjs/neo/pull/5081

since it was causing multiple new bugs. e.g. NumberField extends TextField. so if you just transform whatever type of value which is coming in into a string, it will break.

also, we do need a proper if condition for:

data.value ? data.value.toString().trim() : me.emptyValue

if data.value equals 0, it will get changed to the emptyValue.