Previously, it was possible for Spring Integration, including its
built-in Micrometer support, to be auto-configured before the
Micrometer auto-configuration had defined the MeterRegistry bean. This
resulted in missing Spring Integration metrics.

Spring Integration is unusual in having its own built-in Micrometer
support that it configures itself. Rather than providing
auto-configuration for Integration's Micrometer support (Which isn't
needed), this commit introduces some auto-configuration that just
affects the ordering of the auto-configuration classes. This ordering
ensures that the MeterRegistry bean has been defined by Spring
Integration is auto-configured. This ensures that the MeterRegistry
bean is known to the BeanFactory when Spring Integration goes looking
for it.

See gh-24095