SpringBoot EmbeddedWebServerFactoryCustomizerAutoConfiguration should not run when embedded web server is not configured

When a Spring Boot application is configured for external web container deployment as suggested in the documentation, the EmbeddedWebServerFactoryCustomizerAutoConfiguration will be invoked even though an embedded web server is not set up. This can prevent the app from starting when the auto-configured WebServerFactoryCustomizer is applied.

Comment From: philwebb

Closing in favor of PR #34332. Thanks @terminux!