fix: iosmacos channel name

Author: MichaelVerdon

packages/firebase_database/firebase_database/ios/firebase_database/Sources/firebase_database/FLTFirebaseDatabasePlugin.swift

@@ -20,6 +20,9 @@ import Foundation
 #endif
 import FirebaseDatabase
 
+// Channel name constant to match macOS implementation
+let FLTFirebaseDatabaseChannelName = "plugins.flutter.io/firebase_database"
+
 @objc(FLTFirebaseDatabasePlugin)
 public class FLTFirebaseDatabasePlugin: NSObject, FlutterPlugin, FLTFirebasePluginProtocol {
   private var binaryMessenger: FlutterBinaryMessenger

packages/firebase_database/firebase_database/macos/firebase_database/Sources/firebase_database/FLTFirebaseDatabasePlugin.swift

@@ -13,6 +13,9 @@ import Foundation
   import firebase_core_shared
 #endif
 
+// Channel name constant to match iOS implementation
+let FLTFirebaseDatabaseChannelName = "plugins.flutter.io/firebase_database"
+
 @objc(FLTFirebaseDatabasePlugin)
 public class FLTFirebaseDatabasePlugin: NSObject, FlutterPlugin, FLTFirebasePluginProtocol {
   private var binaryMessenger: FlutterBinaryMessenger