[rubygems/rubygems] Fix missing Gem::Uri.redact on some Ruby 3.1 versions

Our CI did not catch this because it was testing with Ruby 3.1 patch
levels that include a RubyGems version that already has
`Gem::Uri.redact`.

We should make sure the system-rubygems workflow always tests against
the oldest supportted Ruby/RubyGems combination.

ruby/rubygems@3b695e3be1

Author: deivid-rodriguez

lib/bundler/rubygems_ext.rb

@@ -455,4 +455,15 @@ def full_name
 
     Package::TarReader::Entry.prepend(FixFullNameEncoding)
   end
+
+  require "rubygems/uri"
+
+  # Can be removed once RubyGems 3.3.15 support is dropped
+  unless Gem::Uri.respond_to?(:redact)
+    class Uri
+      def self.redact(uri)
+        new(uri).redacted
+      end
+    end
+  end
 end