Bump com.graphql-java:graphql-java from 22.3 to 23.1 in /backend

Bumps [com.graphql-java:graphql-java](https://github.com/graphql-java/graphql-java) from 22.3 to 23.1.
- [Release notes](https://github.com/graphql-java/graphql-java/releases)
- [Commits](graphql-java/graphql-java@v22.3...v23.1)

---
updated-dependencies:
- dependency-name: com.graphql-java:graphql-java
  dependency-version: '23.1'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

backend/build.gradle

@@ -47,7 +47,7 @@ dependencies {
     implementation 'org.springframework:spring-web:6.2.1'
     testImplementation 'org.springframework:spring-webflux'
     testImplementation 'org.springframework.graphql:spring-graphql-test'
-    implementation 'com.graphql-java:graphql-java:22.3'
+    implementation 'com.graphql-java:graphql-java:23.1'
     // graphql-java-extended-validation schema directives
     implementation 'com.graphql-java:graphql-java-extended-validation:22.0'
     // graphql-java-extended-scalars