Aggregated function item_count cannot parse "*" and ?[group="<group_name>"] parameters.

Steps to reproduce:

1. Create calculated item
2. At Formula field add "item_count" function with parameters:

item_count(/*/agent.ping) or item_count(/*/agent.ping?[group="<group_name>"])

Expected result: Calculated item should be successfully saved
Actual result: Error is displayed