Update actions to not run check checklist action for Dependabot PRs

[rmccar]

What is the context of this PR?

Fixes: #3200

Updates the check checklist Github action to not run on Dependabot PRs because there is no checklist being added to the Dependabot descriptions this action always fails.

After this is merged the branch protection rules will need to be updated to change from the "Check tasks" actions being required to the "check-tasks" job

How to review this PR

• Check that the check checklist action runs and passes on this PR
• Check that it is skipped on #3196 where I have added the same change for testing

Checklist

This needs to be completed by the person raising the PR.

• [x] I have selected the correct Assignee
• [x] I have linked the correct Issue

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