Add fdroid dummy for PrivacyProUnifiedFeedback (#4907)

Task/Issue URL: https://app.asana.com/0/488551667048375/1208047268001821/f

### Description
Provide a dummy for fdroid builds

### Steps to test this PR

Before the fix `./gradlew assembleFR` would fail
After the fix it should build normally

Author: aitorvs

subscriptions/subscriptions-dummy-impl/src/main/java/com/duckduckgo/subscriptions/impl/feedback/DummyPrivacyProUnifiedFeedback.kt

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2024 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.
+ */
+
+package com.duckduckgo.subscriptions.impl.feedback
+
+import com.duckduckgo.di.scopes.AppScope
+import com.duckduckgo.subscriptions.api.PrivacyProUnifiedFeedback
+import com.duckduckgo.subscriptions.api.PrivacyProUnifiedFeedback.PrivacyProFeedbackSource
+import com.squareup.anvil.annotations.ContributesBinding
+import javax.inject.Inject
+
+@ContributesBinding(AppScope::class)
+class DummyPrivacyProUnifiedFeedback @Inject constructor() : PrivacyProUnifiedFeedback {
+    override suspend fun shouldUseUnifiedFeedback(source: PrivacyProFeedbackSource): Boolean {
+        return false
+    }
+}