SNOW-2107822 : Remove Snyk workflow files

[sfc-gh-hpathak]

1. What Jira ticket or GitHub issue is this PR addressing? Make sure that there is a ticket or issue accompanying your PR.

   Fixes #NNNN/SNOW-NNNNNNN

2. Fill out the following pre-review checklist:

   • I am adding a new automated test(s) to verify correctness of my new code
   • I am adding new logging messages
   • I am adding a new telemetry message
   • I am adding new credentials
   • I am adding a new dependency

3. Please describe how your code solves the related issue.

   Replace this with a short description of how your code change solves the related issue.

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Additional Information

Removing Snyk workflows as these are deprecated / not working. We now have
managed Snyk scans that also open JIRA issues. This also removes internal
repo dependencies.

[sfc-gh-bli]

LGTM