update : remove unused upsert method.

Change-Id: I737c7c0078512594a719fe3966cdd99ead39331f

core/database/src/main/java/com/google/samples/apps/nowinandroid/core/database/dao/UpsertHelper.kt

@@ -1,37 +0,0 @@
-/*
- * Copyright 2022 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.google.samples.apps.nowinandroid.core.database.dao
-
-/**
- * Performs an upsert by first attempting to insert [items] using [insertMany] with the the result
- * of the inserts returned.
- *
- * Items that were not inserted due to conflicts are then updated using [updateMany]
- */
-suspend fun <T> upsert(
-    items: List<T>,
-    insertMany: suspend (List<T>) -> List<Long>,
-    updateMany: suspend (List<T>) -> Unit,
-) {
-    val insertResults = insertMany(items)
-
-    val updateList = items.zip(insertResults)
-        .mapNotNull { (item, insertResult) ->
-            if (insertResult == -1L) item else null
-        }
-    if (updateList.isNotEmpty()) updateMany(updateList)
-}