Allow aliases when parsing Redis configuration

This is a follow-up to
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/58042 which
changed it to use `#safe_load` and causes some config files with aliases
to not work.

lib/gitlab/redis/wrapper.rb

@@ -142,7 +142,7 @@ module Gitlab
       def fetch_config
         return false unless self.class._raw_config
 
-        yaml = YAML.safe_load(self.class._raw_config)
+        yaml = YAML.safe_load(self.class._raw_config, aliases: true)
 
         # If the file has content but it's invalid YAML, `load` returns false
         if yaml