Don't try to decrypt appData unless it is a writeable account

amethyst/src/main/java/com/vitorpamplona/amethyst/model/nip78AppSpecific/AppSpecificState.kt

@@ -64,6 +64,7 @@ class AppSpecificState(
     }
 
     init {
+        if (settings.isWriteable()) {
             settings.backupAppSpecificData?.let { event ->
                 Log.d("AccountRegisterObservers", "Loading saved app specific data ${event.toJson()}")
                 @OptIn(DelicateCoroutinesApi::class)
@@ -103,3 +104,4 @@ class AppSpecificState(
             }
         }
     }
+}