Add ability to manually run npm-audit-fix workflow

[ElizabethSamuel-MSFT]

Thank you for your pull request! Please provide the following information.

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Change Description:

Describe what the PR is about. 

1. Do these changes impact any npm scripts commands (in package.json)? (e.g., running 'npm run start') No
   If Yes, briefly describe what is impacted.

2. Do these changes impact VS Code debugging options (launch.json)? No
   If Yes, briefly describe what is impacted.

3. Do these changes impact template output? (e.g., add/remove file, update file location, update file contents) No
   If Yes, briefly describe what is impacted.

4. Do these changes impact documentation? (e.g., a tutorial on https://docs.microsoft.com/en-us/office/dev/add-ins/overview/office-add-ins) No
   If Yes, briefly describe what is impacted.

If you answered yes to any of these please do the following:
> Include 'Rick-Kirkham' in the review
> Make sure the README file is correct

Validation/testing performed:

Describe manual testing done. 

Did similar change in -samples repo with no issues (can only test in this repo when the change is in the default branch)