The omitzero tag option has been backported to v1 "encoding/json"
from the "encoding/json/v2" prototype and will land in Go1.24.
Until we fully upgrade to Go1.24, adjust the test to be agnostic
to which version of Go someone is using.
Updates tailscale/corp#25406
Signed-off-by: Joe Tsai <joetsai@digital-static.net>