Removing deprecated har-validator library

[davidcao1337]

PR Checklist:

• I have run npm test locally and all tests are passing.
• [N/A] I have added/updated tests for any new behavior.
  
• [N/A] If this is a significant change, an issue has already been created where the problem / solution was discussed: [N/A, or add link to issue here]
  

PR Description

This PR removes the use of the har-validator library which is no longer supported. Since the library is EOL, it poses a security concern.