Lenient json parsing for backup import

app/src/main/java/org/tasks/backup/TasksJsonImporter.kt

@@ -377,7 +377,10 @@ class TasksJsonImporter @Inject constructor(
     }
 
     companion object {
-        private val json = Json { ignoreUnknownKeys = true}
+        private val json = Json {
+            isLenient = true
+            ignoreUnknownKeys = true
+        }
         private val ignorePrefs = intArrayOf(
                 R.string.p_current_version,
                 R.string.p_backups_android_backup_last