They didn't lose kitchen access, just the sink. You can try asking for accommodations while the kitchen sink is out, but I don't see it being required by the LTA. The lack of the kitchen sink doesn't make the place uninhabitable. Since repairs are being made (which was the point of the outage anyhow), then the landlord's duty is met under the act. Doing things for the inconvenience aspects is purely goodwill.
Like I said, you can ask, but I don't see any right to anything.

