fix(lambda): correcting changeset detection

[Vandita2020]

Issue #, if available

Description of changes

With the updates to the parameter values, the changes were not reflected when the changeSet got created, the issue was with the condition used to check if the update is being made.

Previously, the code used type == "Update" to validate if the action was an update, but it should have been changeset_type == "Update".

Description of how you validated changes

Checklist

• Adheres to the development guidelines
• Add/update transform tests
  • Using correct values
  • Using wrong values
• Add/update integration tests

Examples?

Please reach out in the comments if you want to add an example. Examples will be
added to sam init through aws/aws-sam-cli-app-templates.

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

[vicheey]

Do you mind providing PR links to any related changes or bug issues for context?

[valerena]

It's interesting that this is a bug, but it's not related to an issue we discussed offline. So I don't know exactly what this will do (because this only affects SAM's integration tests, and nothing else).