fix(dart): remove macOS git ignore settings

remove macOS git ignore settings

Author: simeng-li

.gitignore

@@ -100,13 +100,6 @@ analysis_benchmark.json
 **/ios/ServiceDefinitions.json
 **/ios/Runner/GeneratedPluginRegistrant.*
 
-# macOS
-**/Flutter/ephemeral/
-**/Pods/
-**/macos/Flutter/GeneratedPluginRegistrant.swift
-**/macos/Flutter/ephemeral
-**/xcuserdata/
-
 # Coverage
 **/coverage/