Issue#129: Clean data after onChange between oneOf

[saicheck2233]

Link: Issue#129

Description: When you select one of the dropdown from the oneOf2, key in some value and select the default empty value in the dropdown, the value is still saved in the container.
For example, select [An object] from the oneOf example and then select []. When you click getData(), the values are still stored in the container.
This kind of situation will mismatch the function getData().
For example select [A multiple of 3] and fill with number 3. The getData() will get the value 3.
However, when you select [] and repeat the function getData(), it will still get the value 3.

Pic before changes:

Select “A multiple of 3” and key in a number, clicking getData() it would return the value of it.

Select the empty selection and click getData(), it would still return the value “3”.

Pic after changes:

Select “A multiple of 3” and key in a number, clicking getData() it would return the value of it.

Select the empty selection and click getData() will now show null.