Restore support for AL2 x86_64 install_shell task

Commit bf467db fixed AL2 aarch64, but broke AL2
x86_64 causing the task to install the `puppetN-release-amazon-2.noarch.rpm`
release package, but later attempts to `yum install puppet-agent` would fail,
since there are no AL2 x86_64 builds.

It also broke future releases of amazon, so the hypothetical AL 2025 would
fallback to el-2025.

This commit results on the following mapping:

AL2 x86_64     -> puppetN-release-el-7.noarch.rpm
AL2 aarch64    -> puppetN-release-amazon-2.noarch.rpm
AL2023 (all)   -> puppetN-release-amazon-2023.noarch.rpm

And ensures future AL releases work as expected.

manifests/osfamily/redhat.pp

@@ -40,8 +40,13 @@
     if ($puppet_agent::is_pe and (!$puppet_agent::use_alternate_sources)) {
       $pe_server_version = pe_build_version()
       # Install amazon packages on AL2 (only aarch64) and 2003 and up (all arch)
-      if $facts['os']['name'] == 'Amazon' and "$amz_el_version" =~ /^(6|7)$/ {
-        $pe_repo_dir = "el-${amz_el_version}-${facts['os']['architecture']}"
+      if $facts['os']['name'] == 'Amazon' {
+        # lint:ignore:only_variable_string
+        $pe_repo_dir = "${amz_el_version}" ? {
+          /^(6|7)$/ => "el-${amz_el_version}-${facts['os']['architecture']}",
+          default   => $facts['platform_tag'],
+        }
+        # lint:endignore
       } else {
         $pe_repo_dir = $facts['platform_tag']
       }

tasks/install_shell.sh

@@ -284,11 +284,6 @@ case $platform in
   "SLES")
     platform_version=$major_version
     ;;
-  "Amzn"|"Amazon Linux")
-    case $platform_version in
-      "2") platform_version="2";;
-    esac
-    ;;
 esac
 
 # Find which version of puppet is currently installed if any
@@ -662,8 +657,11 @@ case $platform in
     info "Amazon platform! Lets get you an RPM..."
     filetype="rpm"
     platform_package="el"
-    # For Amazon Linux 2023 and onwards we can use the 'amazon' packages created instead of 'el' packages
-    if (( $platform_version == 2023 || $platform_version == 2 )); then
+    arch="$(uname -p)"
+    # Install amazon packages on AL2 (only aarch64) and 2003 and up (all arch)
+    if (( $platform_version == 2 && $arch == 'x86_64' )); then
+      platform_version="7"
+    elsif (( $platform_version == 2 || $platform_version >= 2023 )); then
       platform_package="amazon"
     fi
     filename="${collection}-release-${platform_package}-${platform_version}.noarch.rpm"