fix: Update to MorphoCloud/MorphoCloudWorkflow@517b38b

List of MorphoCloudWorkflow changes:

```
$ git shortlog 343fe41..517b38b --no-merges
Jean-Christophe Fillion-Robin (1):
      test2
```

See MorphoCloud/MorphoCloudWorkflow@343fe41...517b38b

.github/actions/extract-issue-fields/action.yml

@@ -59,15 +59,15 @@ runs:
         instance_flavor=$(
           cat <<'EOF' | \
             jq -r '."cloud-computing-instance-flavor".text | split(" - ")[0]'
-        ${{ toJSON(steps.parse.outputs.data) }}
+        ${{ steps.parse.outputs.data }}
         EOF)
         echo "instance_flavor [$instance_flavor]"
         echo "instance_flavor=$instance_flavor" >> $GITHUB_OUTPUT
 
         orcid=$(
           cat <<'EOF' | \
           jq -r ".orcid.text"
-        ${{ toJSON(steps.parse.outputs.data) }}
+        ${{ steps.parse.outputs.data }}
         EOF
         )
         echo "orcid [$orcid]"
@@ -78,7 +78,7 @@ runs:
           cat <<'EOF' | \
           jq -r ".email.text" | \
           sed -E 's/^<([^<>]+)>$/\1/'
-        ${{ toJSON(steps.parse.outputs.data) }}
+        ${{ steps.parse.outputs.data }}
         EOF
         )
         echo "email [$email]"
@@ -89,7 +89,7 @@ runs:
           cat <<'EOF' | \
           jq -r '."confirm-email".text // empty' | \
           sed -E 's/^<([^<>]+)>$/\1/'
-        ${{ toJSON(steps.parse.outputs.data) }}
+        ${{ steps.parse.outputs.data }}
         EOF
         )