Update dependency org.jmailen.kotlinter to v5.4.0 (#54)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

backend/gradle/libs.versions.toml

@@ -8,7 +8,7 @@ gradle_versions_filter = "0.1.16"
 kotest = "6.1.1"
 kotlin_logging = "7.0.14"
 kotlin = "2.3.0"
-kotlinter = "5.3.0"
+kotlinter = "5.4.0"
 kotlinx_coroutines = "1.10.2"
 kotlinx_serialization = "1.10.0"
 ktor = "3.4.0"