fix(cdk): re-enable refresh button for cdk explorer (aws#4418)

The cdk refresh button was inadvertendly disabled in this commit:
aws@4e72ba7

This restores the button.

![image](https://github.com/aws/aws-toolkit-vscode/assets/149123719/9516af10-86d5-43e8-a9b9-c3d163ecee0a)

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## License

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

Co-authored-by: aws-toolkit-automation <>

.changes/next-release/Bug Fix-7858d5db-fde1-4db1-860f-5be3b0bce411.json

@@ -0,0 +1,4 @@
+{
+	"type": "Bug Fix",
+	"description": "CDK Explorer: Refresh button is now visible."
+}

packages/toolkit/package.json

@@ -1373,6 +1373,11 @@
                     "when": "view == aws.explorer",
                     "group": "navigation@5"
                 },
+                {
+                    "command": "aws.cdk.refresh",
+                    "when": "view == aws.cdk",
+                    "group": "navigation@1"
+                },
                 {
                     "command": "aws.login",
                     "when": "view == aws.explorer",