Update delete_workflow

[jkylekelly]

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name: Sanitize Delete Workflow about: Remediates arbitrary file delete

Description

Version 0.1.0 is vulnerable to arbitrary file deletion due to improper input sanitization on the delete_workflow API. This PR ensures the API will only delete JSON files in user_dir.

Checklist

Please check the following items before code is ready to be reviewed.

• [X] Code has passed all tests
• [X] Docstrings have been added/updated in Google Style
• [X] Documentation has been updated
• [X] Code is ready for review

[DavdGao]

@rayrayraykk please check this PR