Build: enforce LambdaMethodReference check at compile-time

[XN137]

Follow-up to #5476 where the last violation was removed

the idea is to reduce review effort by enforcing this preference through a compile-time check instead of an ignorable warning

[kbendick]

This LGTM.

If we find this gets in the way of beneficial code patterns, we can turn it off and suppress those warnings instead, but it is nice to not have to worry about littering the build log with warnings.

[nastra]

@rdblue thoughts on enforcing this at compile time?

[rdblue]

This seems like a good idea to me.