fix(snap): Fix review warnings where non-unique elements appear in the assumes top-level property

This fixes the following review failure:

```text
Error found while validating snap.json::$.assumes: ['command-chain', 'command-chain', 'snapd2.43'] has non-unique elements lint-snap-v2_snap_schema
```

Signed-off-by: 林博仁(Buo-ren Lin) <buo.ren.lin@gmail.com>

Author: brlin-tw

snap/snapcraft.yaml

@@ -60,8 +60,7 @@ adopt-info: main
 
 # Snapd feature set and version the snap requires in order to work
 # https://forum.snapcraft.io/t/snapcraft-top-level-metadata/8334#heading--assumes
-assumes:
-  - command-chain
+assumes: []
 
 # Base runtime
 # The common runtime for the snap to run on, or `bare` for static linked applications