Stop applying Groovy plugin for the root Gradle project

The root project does not rely on the Groovy plugin.

See gh-27945

Author: sbrannen

build.gradle

@@ -363,7 +363,6 @@ configure(moduleProjects) { project ->
 configure(rootProject) {
 	description = "Spring Framework"
 
-	apply plugin: "groovy"
 	apply plugin: "kotlin"
 	apply plugin: "io.spring.nohttp"
 	apply plugin: 'org.springframework.build.api-diff'