Add Gem.disable_system_update_message in setup.rb #7225

Job	Run time
Realworld Bundler against system Rubygems (ruby-3.2)	1m 58s
Realworld Bundler against system Rubygems (ruby-3.3)	2m 4s
Tapioca	1m 9s
Realworld Bundler against system Rubygems (ruby-3.4)	1m 54s
Realworld Bundler on macOS (ruby-3.2)	1m 39s
Realworld Bundler on Ubuntu (ruby-3.4)	1m 59s
Realworld Bundler on Ubuntu (ruby-3.3)	2m 3s
Realworld Bundler on Ubuntu (ruby-3.2)	2m 12s
Realworld Bundler on macOS (ruby-3.4)	1m 37s
Realworld Bundler on macOS (ruby-3.3)	1m 16s
Check unused cassettes	11s
All realworld-bundler jobs pass	4s
	18m 6s

Provide feedback