Use ModulesConfig for push provider modules.

plugins/src/main/kotlin/config/PushProvidersConfig.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2024 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Please see LICENSE in the repository root for full details.
+ */
+
+package config
+
+data class PushProvidersConfig(
+    val includeFirebase: Boolean,
+    val includeUnifiedPush: Boolean,
+) {
+    init {
+        require(includeFirebase || includeUnifiedPush) {
+            "At least one push provider must be included"
+        }
+    }
+}