fix: Update to MorphoCloud/MorphoCloudWorkflow@46b0286

List of MorphoCloudWorkflow changes:

```
$ git shortlog 6aaadea..46b0286 --no-merges
Jean-Christophe Fillion-Robin (1):
      fix(create-instance): Skip copying Slicer if already exists
```

See MorphoCloud/MorphoCloudWorkflow@6aaadea...46b0286

.github/workflows/create-instance.yml

@@ -477,7 +477,7 @@ jobs:
             -o UserKnownHostsFile=/dev/null \
             -o LogLevel=ERROR \
             exouser@$INSTANCE_IP \
-            'mv /media/volume/MyData-tmp/Slicer /media/volume/MyData/Slicer && mv /media/volume/MyData-tmp/dist /media/volume/MyData/dist'
+            '[ ! -d /media/volume/MyData/Slicer ] && mv /media/volume/MyData-tmp/Slicer /media/volume/MyData/Slicer; mv /media/volume/MyData-tmp/dist /media/volume/MyData/dist'
         env:
           INSTANCE_IP: ${{ steps.ip_create.outputs.floating_ip_address }}