Remove WebFluxExtensionInitializer and tests

Delete WebFluxExtensionInitializer and its unit test. Update META-INF/spring.factories to remove the ApplicationContextInitializer registration for WebFluxExtensionInitializer and keep only the SpringWebFluxHelper entry. This cleans up the unused initializer and its associated test and factory registration.

Author: mercyblitz

microsphere-spring-webflux/src/main/java/io/microsphere/spring/webflux/annotation/WebFluxExtensionInitializer.java

@@ -1,7 +1,3 @@
 # SpringWebHelper
 io.microsphere.spring.web.util.SpringWebHelper=\
-io.microsphere.spring.webflux.util.SpringWebFluxHelper
-
-# ApplicationContextInitializer
-org.springframework.context.ApplicationContextInitializer=\
-io.microsphere.spring.webflux.annotation.WebFluxExtensionInitializer
+io.microsphere.spring.webflux.util.SpringWebFluxHelper