Account for RHEL in dnf5 vs dnf conditional

Summary:
The conditional added in the following Github commit did not take RHEL into account: facebook@e86019c. We do this by switching from Centos min version -> EL min version, which includes both RHEL and Centos

Also, taking this opportunity to simplify the conditional by using <os>_min_version? helpers from fb_helpers based on Github feedback.

Differential Revision: D74013493

fbshipit-source-id: de3fb57adae8e93e5bfccc807e5a56b42afab34e

Author: ryantimwilson

cookbooks/fb_dnf/recipes/packages.rb

@@ -28,9 +28,7 @@
   python3-libcomps
 }
 
-if (node.fedora? && node['platform_version'].to_i >= 41) ||
-   (node.centos? && node['platform_version'].to_i >= 11) ||
-   node.eln?
+if node.fedora_min_version?(41) || node.el_min_version?(11) || node.eln?
   dnf_packages += %w{dnf5 dnf5-plugins}
 else
   dnf_packages += %w{dnf dnf-plugins-core dnf-utils}