fix(deps): update dependency org.jetbrains.kotlinx:kotlinx-serialization-json to v1.8.1

Author: renovate[bot]

gradle/libs.versions.toml

@@ -5,7 +5,7 @@ agp = "8.9.1"
 firebase-firestore = "25.1.3"
 firebase-database = "21.0.0"
 kotlinx-datetime = "0.6.2"
-kotlinx-serialization = "1.8.0"
+kotlinx-serialization = "1.8.1"
 mockk = "1.13.17"
 
 androidx-test = "1.6.1"