Revert "Drop plasma-nm-l2tp for now"

go-l2tp has been vendored and renamed.

This reverts commit 666533e.

Author: yselkowitz

configs/eln_extras_kde_plasma.yaml

@@ -93,17 +93,17 @@ data:
   arch_packages:
     x86_64:
       - bluedevil
-      #- plasma-nm-l2tp
+      - plasma-nm-l2tp
       - plasma-nm-openconnect
       - plasma-sdk
     aarch64:
       - bluedevil
-      #- plasma-nm-l2tp
+      - plasma-nm-l2tp
       - plasma-nm-openconnect
       - plasma-sdk
     ppc64le:
       - bluedevil
-      #- plasma-nm-l2tp
+      - plasma-nm-l2tp
       - plasma-nm-openconnect
       - plasma-sdk
   labels: