Update kotlin to v2.4.21

gradle/libs.versions.toml

@@ -9,7 +9,7 @@ sqlite = "3.53.2.0"
 mariadb = "3.5.9"
 androidx-lifecycle = "2.10.0"
 compose-multiplatform = "1.12.2"
-kotlin = "2.4.10"
+kotlin = "2.4.21"
 kotlinx-coroutines = "1.11.0"
 ktor = "3.5.1"
 spring-sec = "7.1.0"