The force-commit flag is used to force the commit of an address or a route from DHCP/RA even when it was removed from platform externally (for example because it expired). Routes generated from the l3cd should also have the flag set.
Without this, NM properly re-adds the DHCP address after the lease is lost and obtained again, but fails to add the prefix-route.
Fixes: 2838b1c5 ('core: track force-commit flag for l3cd and platform objects')