Support empty values for Numbers case

Actual:
Right now an empty value for a field with Number type leads to NumberFormatException.
The field is not required but still, we require value for it.
Expected:
Null value.

Suggestion:
Check that if the passed value is empty -> return the null value without conversion.
Now it leads to the NumberFormatException. That's why I think this won't create a regression.

https://github.com/Talend/component-runtime/blob/78bbe2710764343b617dbece90cc0e9f24106087/component-runtime-manager/src/main/java/org/talend/sdk/component/runtime/manager/xbean/registry/EnrichedPropertyEditorRegistry.java#L77