feat(toolkit): Enhance autocomplete for variable and JSONata expression in JSON ASL files. (aws#6478)

## Feature description

Step Functions: Upgrade amazon-states-language-service to 1.15. This new
version enhance autocomplete for variable and JSONata expression in JSON
ASL files.


[Variables and
JSONata](https://aws.amazon.com/blogs/compute/simplifying-developer-experience-with-variables-and-jsonata-in-aws-step-functions/)
was a Step Funtions feature released in 2024 Nov

### Demo:

![jsonata-autocomplete](https://github.com/user-attachments/assets/ee9d01e7-8458-480a-8568-d34a6b862b87)

---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Co-authored-by: Silvia Chen <[email protected]>

Author: silviac98

package-lock.json

@@ -519,7 +519,7 @@
         "@vscode/debugprotocol": "^1.57.0",
         "@zip.js/zip.js": "^2.7.41",
         "adm-zip": "^0.5.10",
-        "amazon-states-language-service": "^1.13.0",
+        "amazon-states-language-service": "^1.15.0",
         "async-lock": "^1.4.0",
         "aws-sdk": "^2.1692.0",
         "aws-ssm-document-language-service": "^1.0.0",

packages/core/package.json

@@ -0,0 +1,4 @@
+{
+	"type": "Feature",
+	"description": "Step Functions: Upgrade amazon-states-language-service to 1.15. This new version enhance autocomplete for variable and JSONata expression in JSON ASL files."
+}