chore(deps): bump org.jetbrains.kotlin.android in /android

Bumps [org.jetbrains.kotlin.android](https://github.com/JetBrains/kotlin) from 2.2.20 to 2.3.21.
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v2.2.20...v2.3.21)

---
updated-dependencies:
- dependency-name: org.jetbrains.kotlin.android
  dependency-version: 2.3.21
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

android/settings.gradle.kts

@@ -20,7 +20,7 @@ pluginManagement {
 plugins {
     id("dev.flutter.flutter-plugin-loader") version "1.0.0"
     id("com.android.application") version "8.11.1" apply false
-    id("org.jetbrains.kotlin.android") version "2.2.20" apply false
+    id("org.jetbrains.kotlin.android") version "2.3.21" apply false
 }
 
 include(":app")