phase 1: update waffle no request default (#24392)

This is Phase 1 of a 2 part rollout.

Here, we want to ensure that checking if the waffle flag
is set to active for everyone would provide the same value
as the current implementation for calls that have no request.
The current implementation is to use flag_undefined_default,
which is deprecated and we are trying to remove.

We are adding a custom metric to see if they match in
Production. If all goes well, in Phase 2 we will switch to
this new approach.

ARCHBOM-1331