chore(deps): Bump kotlin from 1.9.10 to 1.9.21

Bumps `kotlin` from 1.9.10 to 1.9.21.

Updates `org.jetbrains.kotlin.android` from 1.9.10 to 1.9.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.9.10...v1.9.21)

Updates `org.jetbrains.kotlin.multiplatform` from 1.9.10 to 1.9.21
- [Release notes](https://github.com/JetBrains/kotlin/releases)
- [Changelog](https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md)
- [Commits](JetBrains/kotlin@v1.9.10...v1.9.21)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

gradle/libs.versions.toml

@@ -4,7 +4,7 @@ androidx-activity = "1.8.0"
 androidx-compose-bom = "2023.10.01" # https://developer.android.com/jetpack/compose/bom/bom-mapping
 androidx-compose-compiler = "1.5.3" # https://developer.android.com/jetpack/androidx/releases/compose-kotlin#pre-release_kotlin_compatibility
 jetbrains-compose = "1.5.3"
-kotlin = "1.9.10"
+kotlin = "1.9.21"
 
 [libraries]
 androidx-activity = { module = "androidx.activity:activity", version.ref = "androidx-activity" }