Remove not used OnDiscoveryExpiration callback (#21486)
Remove not used OnDiscoveryExpiration callback (#21486)

It seems that this is a leftover from #20007.
project-chip/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip