fix: fix console warning regarding undefined required prop

During transition between scenarios with different run templates, the default
value for a given scenario parameter may temporarily not be available. This leads
to console warnings because the defaultParameterValue prop was decalred as required.
Yet, it does not need to be required: the component could use null or undefined as a
default value, or wait for the actual default value to be retrieved during
transitions between scenarios.

src/components/ScenarioParameters/components/ScenarioParametersInputs/GenericNumberInput.js

@@ -77,9 +77,10 @@ GenericNumberInput.propTypes = {
   context: PropTypes.object.isRequired,
   parameterValue: PropTypes.any,
   setParameterValue: PropTypes.func.isRequired,
-  defaultParameterValue: PropTypes.number.isRequired,
+  defaultParameterValue: PropTypes.number,
   isDirty: PropTypes.bool,
 };
+
 GenericNumberInput.defaultProps = {
   isDirty: false,
 };