fix(snap): set plugin to nil [skip ci]

stores/snapcraft/insider/snap/snapcraft.yaml

@@ -11,6 +11,7 @@ compression: lzo
 
 parts:
   codium-insiders:
+    plugin: nil
     override-build: |
       set -eu
       # Get .deb url

stores/snapcraft/stable/snap/snapcraft.yaml

@@ -11,6 +11,7 @@ compression: lzo
 
 parts:
   codium:
+    plugin: nil
     override-build: |
       set -eu
       # Get .deb url