It is not necessary, because the blocked events are sorted by time.
Anyway, SWH uses the events from Windows Event Log, so they can be cleared by using Event Viewer or Wevtutil tool. For example, open the CMD with Administrator privileges and use the below CmdLines:
wevtutil.exe cl "Microsoft-Windows-PowerShell/Operational"
wevtutil.exe cl "Application"
The first will clear the PowerShell events and the second SRP events. But, also many other events will be cleared in these channels, so I think that it would be better to avoid clearing the blocked events.