Create VersionCatalogExtensions

- VersionCatalog.getPlugin

Change-Id: I9731877a9a583d3428b600bfdbcffc016facd768

build-logic/convention/src/main/kotlin/com/google/samples/apps/nowinandroid/VersionCatalogExtensions.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2024 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
+
+import org.gradle.api.artifacts.VersionCatalog
+import kotlin.jvm.optionals.getOrNull
+
+/**
+ * Get a Plugin from version catalog using an alias.
+ */
+fun VersionCatalog.getPlugin(alias: String): String =
+    findPlugin(alias).getOrNull()?.get()?.pluginId ?: ""