Directly grab map values instead of using loop-clause variables when setting up federated sync controller tests.

Go's loop-clause variables are allocated once and the items are copied
to that variable while iterating through the loop. This means, these
variables can't escape the scope since closures are bound to loop-clause
variables whose value change during each iteration. Doing so would lead
to undesired behavior. For more on this topic see:
https://github.com/golang/go/wiki/CommonMistakes

So in order to workaround this problem in sync controller e2e tests, we
iterate through the map and copy the map value to a variable inside the
loop before using it in closures.

Fixes issue: #47059