I can see that you have also submitted a private support thread asking the same question.
I will paste the response here for future reference, in case you have further questions, please let us resolve them privately and then we can update this public forum.
When in edit mode the numeric displays the actual number value (js number) - not a string. Thus, it is not possible to format it.
However, you could achieve the described behavior by handling the input event handler of an input element.
var value = $(e.target).val();
var number = parseFloat(value.replace(/,/g, ''));
var newValue = isNaN(number) ? 0 : number;
Below you will find a small sample which demonstrates the above approach:
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