Bump io.spring.dependency-management from 1.1.6 to 1.1.7 in /backend

Bumps [io.spring.dependency-management](https://github.com/spring-gradle-plugins/dependency-management-plugin) from 1.1.6 to 1.1.7.
- [Release notes](https://github.com/spring-gradle-plugins/dependency-management-plugin/releases)
- [Commits](spring-gradle-plugins/dependency-management-plugin@v1.1.6...v1.1.7)

---
updated-dependencies:
- dependency-name: io.spring.dependency-management
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

backend/build.gradle.kts

@@ -2,7 +2,7 @@ plugins {
     java
     application
     id("org.springframework.boot") version "3.4.1"
-    id("io.spring.dependency-management") version "1.1.6"
+    id("io.spring.dependency-management") version "1.1.7"
     id("net.ltgt.errorprone") version "4.1.0"
 }