Require that const_get does not inherit constant scope (false as 2nd arg)

Description of the proposal

Require const_get calls to use false as the second argument. This means const_get calls don't retrieve constants from higher level scopes.

Consider the code below (in Rails, not pure Ruby):

module Gitlab
  module Prometheus
  end
end

module Prometheus
end

Object.const_get("Gitlab::Prometheus")

should not return the Prometheus constant. It should return the Gitlab::Prometheus.

This affects only development and test environments. production is not affected because it eager_load all constants.

MR that implements this: !18048 (merged)

Mention the proposal in the next backend weekly call and the #backend channel to encourage contribution
Proceed with the proposal once 50% of the maintainers have weighed in, and 80% of the votes are 👍
Once approved, mention it again in the next backend weekly call and the #backend channel