Remove deprecated Ruby File.exists? in helper script (#110045)

diff --git a/packages/flutter_tools/bin/podhelper.rb b/packages/flutter_tools/bin/podhelper.rb
index 972679c..266adfc 100644
--- a/packages/flutter_tools/bin/podhelper.rb
+++ b/packages/flutter_tools/bin/podhelper.rb
@@ -272,7 +272,7 @@
 # https://flutter.dev/go/plugins-list-migration
 def flutter_parse_plugins_file(file, platform)
   file_path = File.expand_path(file)
-  return [] unless File.exists? file_path
+  return [] unless File.exist? file_path
 
   dependencies_file = File.read(file)
   dependencies_hash = JSON.parse(dependencies_file)