[Tech] Bump org.springframework.security:spring-security-test

Bumps [org.springframework.security:spring-security-test](https://github.com/spring-projects/spring-security) from 6.1.5 to 6.2.4.
- [Release notes](https://github.com/spring-projects/spring-security/releases)
- [Changelog](https://github.com/spring-projects/spring-security/blob/main/RELEASE.adoc)
- [Commits](spring-projects/spring-security@6.1.5...6.2.4)

---
updated-dependencies:
- dependency-name: org.springframework.security:spring-security-test
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

backend/build.gradle.kts

@@ -63,7 +63,7 @@ dependencies {
     api("com.google.code.gson:gson:2.10.1")
     api("org.springframework.boot:spring-boot-starter-cache:3.2.5")
     api("com.github.ben-manes.caffeine:caffeine:3.1.5")
-    api("org.springframework.security:spring-security-test:6.1.5")
+    api("org.springframework.security:spring-security-test:6.2.4")
     api("org.testcontainers:testcontainers:1.19.2")
     api("io.hypersistence:hypersistence-utils-hibernate-63:3.7.5")
     api("org.assertj:assertj-core:3.24.2")