Use Development environment for Sync by default in Debug builds (#2013)

Task/Issue URL: https://app.asana.com/0/414235014887631/1205489036222324/f

Description:
When running the app from Xcode, use Development environment for Sync by default.

DuckDuckGo/AppDelegate.swift

@@ -191,12 +191,18 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
         // MARK: Sync initialisation
 
+#if DEBUG
+        let defaultEnvironment = ServerEnvironment.development
+#else
+        let defaultEnvironment = ServerEnvironment.production
+#endif
+
         let environment = ServerEnvironment(
             UserDefaultsWrapper(
                 key: .syncEnvironment,
-                defaultValue: ServerEnvironment.production.description
+                defaultValue: defaultEnvironment.description
             ).wrappedValue
-        ) ?? .production
+        ) ?? defaultEnvironment
 
         syncDataProviders = SyncDataProviders(bookmarksDatabase: bookmarksDatabase, secureVaultErrorReporter: SecureVaultErrorReporter.shared)
         let syncService = DDGSync(dataProvidersSource: syncDataProviders, errorEvents: SyncErrorHandler(), log: .syncLog, environment: environment)