added value type check to the aggregation context. The idea here is that when we check if the agg. context accepts a value for a specific value source key, we also need to provide the context the value type that we're dealing with. So for example, if there is a date agg (say range), and somewhere down its hierarchy there's an avg agg. which is not configured with a field. The value source for the avg agg will be picked up from the context (it will not be the date range though)... and each value will be evaluated, the avg agg will ask whether the value is accepted by the context... if the date range will recieve this request, it might accept it as it might think it refers to the date value (which is also numeric) but the check should actually be done by the aggregation from which the value came from
integrated value parser