[Tech] Bump io.ktor:ktor-serialization-kotlinx-json-jvm in /backend

Bumps [io.ktor:ktor-serialization-kotlinx-json-jvm](https://github.com/ktorio/ktor) from 2.3.12 to 3.0.1.
- [Release notes](https://github.com/ktorio/ktor/releases)
- [Changelog](https://github.com/ktorio/ktor/blob/main/CHANGELOG.md)
- [Commits](ktorio/ktor@2.3.12...3.0.1)

---
updated-dependencies:
- dependency-name: io.ktor:ktor-serialization-kotlinx-json-jvm
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

backend/build.gradle.kts

@@ -59,7 +59,7 @@ dependencies {
     api("io.ktor:ktor-client-core-jvm:2.3.12")
     api("io.ktor:ktor-client-java-jvm:2.3.12")
     api("io.ktor:ktor-client-content-negotiation-jvm:2.3.12")
-    api("io.ktor:ktor-serialization-kotlinx-json-jvm:2.3.12")
+    api("io.ktor:ktor-serialization-kotlinx-json-jvm:3.0.1")
     api("org.hibernate.validator:hibernate-validator:8.0.1.Final")
     api("jakarta.validation:jakarta.validation-api:3.1.0")
     api("com.fasterxml.jackson.module:jackson-module-kotlin:2.18.0")