This reverts commit 9dd7b068.

Closes gh-11951

This reverts commit f24c92c6 which is
no longer necessary as SPR-16456 has no been fixed.

See gh-11894

* pr/12017:
  Polish "Remove unnecessary config options for metrics"
  Remove unnecessary config options for JDBC, Rabbit, and Cache metrics

Closes gh-12017"

See gh-12017

Closes gh-12012

Closes gh-11916

Closes gh-12010

* pr/11997:
  Polish "Add health indicator for reactive MongoDB"
  Add health indicator for reactive MongoDB

Closes gh-11997

See gh-11997

Closes gh-12006

* pr/12019:
  Polish "Polish modifier order"
  Polish modifier order

Closes gh-12019

See gh-12019

* pr/12011:
  Polish "Remove redundant casts"
  Remove redundant casts

Closes gh-12011

See gh-12011

Migrate `IntegrationAutoConfigurationTests` to use the
`ApplicationContextRunner`.

Update `ApplicationContextAssert` with support for scopes. Allows
tests to consider the all ancestors, or limit assertions to just the
current context.

Fixes gh-12015

Update `ConfigurationPropertySources` so that the underlying sources
are checked when attaching. Prior to this commit, in a parent/child
setup the `ConfigurationPropertySources` adapter may already present
on the parent. This means the attaching is skipped but the managed
sources are incorrect.

Fixes gh-12013

Add `ApplicationContextInitializer` support to
`ApplicationContextRunner`.

Closes gh-11928

Fixes gh-12014

Remove custom `SpringIntegrationMetrics` and instead provide
auto-configuration to the direct Micrometer support added in Spring
Integration 5.0.2.

Closes gh-11985

Closes gh-11970

Closes gh-11978

Closes gh-11970

* pr/12004:
  Polish

Closes gh-12004

Closes gh-11992

As discussed in gh-11872, `TestRestTemplate` constructor variants taking
a `RestTemplate` argument are confusing since the main goal of that
class is to mutate `RestTemplate`.

This commit removes all those constructor variants and replaces them
with `RestTemplateBuilder` arguments when possible.

Closes gh-11872

Closes gh-11025