build: (deps): bump unifiedpush from 5.0.2 to 6.0.2

Bumps unifiedpush from 5.0.2 to 6.0.2.

---
updated-dependencies:
- dependency-name: unifiedpush
  dependency-version: 6.0.2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

android/app/build.gradle.kts

@@ -16,6 +16,22 @@ dependencies {
     coreLibraryDesugaring("com.android.tools:desugar_jdk_libs:2.1.4") // For flutter_local_notifications // Workaround for: https://github.com/MaikuB/flutter_local_notifications/issues/2286
 }
 
+
+// Workaround for https://pub.dev/packages/unifiedpush#the-build-fails-because-of-duplicate-classes
+configurations.all {
+    // Use the latest version published: https://central.sonatype.com/artifact/com.google.crypto.tink/tink-android
+    val tink = "com.google.crypto.tink:tink-android:1.17.0"
+    // You can also use the library declaration catalog
+    // val tink = libs.google.tink
+    resolutionStrategy {
+        force(tink)
+        dependencySubstitution {
+            substitute(module("com.google.crypto.tink:tink")).using(module(tink))
+        }
+    }
+}
+
+
 android {
     namespace = "chat.fluffy.fluffychat"
     compileSdk = flutter.compileSdkVersion