[Tech] Bump io.ktor:ktor-client-mock-jvm in /backend

Bumps [io.ktor:ktor-client-mock-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-client-mock-jvm
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

backend/build.gradle.kts

@@ -79,7 +79,7 @@ dependencies {
     api("io.sentry:sentry-log4j2:7.16.0")
     implementation("org.springframework.cloud:spring-cloud-gateway-mvc:4.1.5")
     runtimeOnly("org.postgresql:postgresql:42.7.4")
-    testImplementation("io.ktor:ktor-client-mock-jvm:2.3.12")
+    testImplementation("io.ktor:ktor-client-mock-jvm:3.0.1")
     testImplementation("org.assertj:assertj-core:3.26.3")
     testImplementation("org.testcontainers:postgresql:1.20.3")
     testImplementation("org.testcontainers:testcontainers:1.20.3")