Flaky test: Test/WrrLocality/custom_lb_least_request

[easwars]

https://github.com/grpc/grpc-go/actions/runs/6040246934/job/16390703192?pr=6597

[zasweq]

I'm hoping this goes away with the least request fix prs that are out (#6587, #6602). Will keep an eye on this though.

[arvindbr8]

https://github.com/grpc/grpc-go/actions/runs/6780271091/job/18428686081?pr=6672

[zasweq]

Being tracked by #6914.

[easwars]

https://github.com/grpc/grpc-go/actions/runs/9701935581/job/26776632867?pr=7357

[arvindbr8]

https://github.com/grpc/grpc-go/actions/runs/9915455818/job/27396327392?pr=7409

[easwars]

https://github.com/grpc/grpc-go/actions/runs/10378063709/job/28733582817?pr=7465

[easwars]

https://github.com/grpc/grpc-go/actions/runs/10396329252/job/28790127397?pr=7502