ADS: Add Theme Preview as internal (#6974)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/1202552961248957/task/1211716283511367?focus=true

### Description
Adds the ADS preview as an internal feature

### Steps to test this PR

_Play Flavour_
- [x] Open the app installing the Play flavour
- [x] Navigate to settings
- [x] Verify that the ADS Preview feature is not visible

_Internal Flavour_
- [x] Open the app installing the Internal flavour
- [x] Navigate to settings
- [x] Verify that the ADS Preview feature is visible

(cherry picked from commit e355592)

Author: malmstein

android-design-system/design-system-internal/.gitignore

@@ -0,0 +1 @@
+/build

android-design-system/design-system-internal/build.gradle

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2025 DuckDuckGo
+ *
+ * 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
+ *
+ *     http://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.
+ */
+
+plugins {
+    id 'com.android.library'
+    id 'kotlin-android'
+    id 'com.squareup.anvil'
+}
+
+apply from: "$rootProject.projectDir/gradle/android-library.gradle"
+
+android {
+    anvil {
+        generateDaggerFactories = true // default is false
+    }
+    namespace 'com.duckduckgo.common.ui.internal'
+}
+
+dependencies {
+
+    implementation "com.squareup.logcat:logcat:_"
+
+    implementation project(path: ':common-utils')
+    implementation project(path: ':design-system')
+
+    implementation project(path: ':di')
+    anvil project(path: ':anvil-compiler')
+    implementation project(path: ':anvil-annotations')
+    implementation project(path: ':app-build-config-api')
+    implementation project(':internal-features-api')
+    implementation project(path: ':navigation-api')
+
+    implementation AndroidX.appCompat
+    implementation Google.android.material
+    implementation AndroidX.constraintLayout
+    implementation AndroidX.core.splashscreen
+    implementation AndroidX.recyclerView
+    implementation AndroidX.lifecycle.viewModelKtx
+    // just to get the dagger annotations
+    implementation Google.dagger
+
+}

design-system/src/main/java/com/duckduckgo/common/ui/themepreview/ui/AppComponentsSettingsFeature.kt renamed to android-design-system/design-system-internal/src/main/java/com/duckduckgo/common/ui/internal/ThemePreviewInternalFeature.kt

@@ -14,10 +14,11 @@
  * limitations under the License.
  */
 
-package com.duckduckgo.common.ui.themepreview.ui
+package com.duckduckgo.common.ui.internal
 
 import android.content.Context
 import com.duckduckgo.anvil.annotations.PriorityKey
+import com.duckduckgo.common.ui.themepreview.ui.AppComponentsActivity
 import com.duckduckgo.di.scopes.AppScope
 import com.duckduckgo.internal.features.api.InternalFeaturePlugin
 import com.squareup.anvil.annotations.ContributesMultibinding
@@ -37,6 +38,6 @@ class ThemesPreviewInternalFeature @Inject constructor(private val context: Cont
     }
 
     override fun onInternalFeatureClicked(activityContext: Context) {
-        activityContext.startActivity(AppComponentsActivity.intent(activityContext))
+        activityContext.startActivity(AppComponentsActivity.Companion.intent(activityContext))
     }
 }

app/build.gradle

@@ -273,6 +273,7 @@ dependencies {
     implementation project(':experiments-impl')
     implementation project(':common-utils')
     implementation project(':app-store')
+    internalImplementation project(':design-system-internal')
     implementation project(':design-system')
     implementation project(':di')
     implementation project(':app-tracking-api')