Remove BaseCallback, it's actually not ideal when looking for usage.

libraries/architecture/src/main/kotlin/io/element/android/libraries/architecture/navigation/BaseCallback.kt

@@ -1,17 +0,0 @@
-/*
- * Copyright (c) 2025 Element Creations Ltd.
- *
- * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
- * Please see LICENSE files in the repository root for full details.
- */
-
-package io.element.android.libraries.architecture.navigation
-
-import com.bumble.appyx.core.plugin.Plugin
-
-/**
- * Base callback interface to be implemented by callers to handle results from nodes.
- */
-fun interface BaseCallback : Plugin {
-    fun onDone()
-}