Disable RuntimeHints tests with the agent

Tests with the agent are broken now that hints for an annotation is
no longer required if the annotated element has an introspection hint.

See gh-28967

spring-context/spring-context.gradle

@@ -1,7 +1,3 @@
-plugins {
-	id 'org.springframework.build.runtimehints-agent'
-}
-
 description = "Spring Context"
 
 apply plugin: "kotlin"