Remove duplicated dependency

See gh-42442

Author: quaff

spring-boot-project/spring-boot-tools/spring-boot-test-support-docker/build.gradle

@@ -14,7 +14,6 @@ dependencies {
 	compileOnly("org.junit.jupiter:junit-jupiter")
 	compileOnly("org.springframework:spring-core")
 
-	optional("org.testcontainers:cassandra")
 	optional("org.testcontainers:cassandra")
 	optional("org.testcontainers:couchbase")
 	optional("org.testcontainers:elasticsearch")