feat: raise Kotlin to 1.9.21

References https://outsystemsrd.atlassian.net/browse/RNMT-6402

Author: EiyuuZack

framework/cdv-gradle-config-defaults.json

@@ -5,7 +5,7 @@
     "GRADLE_VERSION": "8.4",
     "MIN_BUILD_TOOLS_VERSION": "34.0.0",
     "AGP_VERSION": "8.2.0-rc03",
-    "KOTLIN_VERSION": "1.9.10",
+    "KOTLIN_VERSION": "1.9.21",
     "ANDROIDX_APP_COMPAT_VERSION": "1.6.1",
     "ANDROIDX_WEBKIT_VERSION": "1.7.0",
     "ANDROIDX_CORE_SPLASHSCREEN_VERSION": "1.0.1",