refactor(example): package specific examples instead of a single example

packages/fl_query/example/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -0,0 +1,12 @@
+//
+//  Generated file. Do not edit.
+//
+
+import FlutterMacOS
+import Foundation
+
+import connectivity_plus_macos
+
+func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+  ConnectivityPlugin.register(with: registry.registrar(forPlugin: "ConnectivityPlugin"))
+}