as stated, that chain just drives the oil pump, a fair bit of slack is normal, there is no tensioner, yours looks fine in the picture, I wouldn't worry about it. I am rebuilding a 2008 CBR1000RR and they use the same thing, a small chain to drive the oil and water pump, and no tensioner!!
No need to replace it. All are slack from manufacture, and none of the bike's reaching over 200k kms needed to change them.
That chain runs totally in oil, and it is not subject to big loads or load changes as it drives a hidraulic pump.
What doesn't break doesn't have to be repaired.