This commit updates LoggingApplicationListener to register the logging
shutdown hook by default.
The hook is detrimental in a war deployment as it may pin parts of an
application in memory after it has been undeployed. For this reason,
the hook is still disabled by default in war deployments. This is
achieved by setting an attribute on the servlet context in
SpringBootServletInitializer that is then consumed via the Environment
by LoggingApplicationListener.
Closes gh-25046
9713bfc765