chore(deps): update kotlin to v2.1.21 (#428)

Author: renovate[bot]

gradle/libs.versions.toml

@@ -29,7 +29,7 @@ test-androidx-rules = "1.6.1"
 androidx-tracing = "1.3.0"
 uiautomator = "2.3.0"
 okhttp3 = "4.12.0"
-kotlin = "2.1.20"
+kotlin = "2.1.21"
 plugin-oss-licenses = "0.10.6"
 ktlint = "12.2.0"
 detekt = "1.23.8"