fix: Ensure template output is actually parsable data

[lucashuy]

Which issue(s) does this change fix?

#5955

Why is this change necessary?

A change was made to a template fetching method a while back that updated the returned value from the API to be a string instead of a dictionary. The API call itself can return either a string, or a dictionary.

The method did not account for the returned data from the API being a dictionary, and instead the string representation of a Python dictionary object was returned, instead of a JSON formatted string.

How does it address the issue?

Updates the method to return a JSON formatted string if it is a dictionary type.

What side effects does this change have?

None.

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

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