chore(deps): bump org.mariadb.jdbc:mariadb-java-client in /backend

Bumps [org.mariadb.jdbc:mariadb-java-client](https://github.com/mariadb-corporation/mariadb-connector-j) from 3.5.6 to 3.5.7.
- [Release notes](https://github.com/mariadb-corporation/mariadb-connector-j/releases)
- [Changelog](https://github.com/mariadb-corporation/mariadb-connector-j/blob/main/CHANGELOG.md)
- [Commits](mariadb-corporation/mariadb-connector-j@3.5.6...3.5.7)

---
updated-dependencies:
- dependency-name: org.mariadb.jdbc:mariadb-java-client
  dependency-version: 3.5.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

backend/build.gradle

@@ -146,7 +146,7 @@ subprojects {
         implementation 'org.xerial:sqlite-jdbc:3.51.1.0'
         implementation 'com.h2database:h2:2.4.240'
         implementation 'org.postgresql:postgresql:42.7.9'
-        implementation 'org.mariadb.jdbc:mariadb-java-client:3.5.6'
+        implementation 'org.mariadb.jdbc:mariadb-java-client:3.5.7'
 
         implementation "io.ktor:ktor-client-core:$ktor_version"
         //Using Apache Engine Ktor engine, because it is at this time the only one that supports following redirects