fix: skip running tests on changes in validate-deploy-docs.yaml

[siddharth-khatsuriya]

Description

• Since we now have a new validate-deploy-docs.yaml workflow for documentation, we are including it in the list of files considered as documentation-only changes. This ensures that test cases will not be triggered when only documentation workflows are modified.

Checklist

• README.md has been updated or is not required
• push trigger tests
• manual release test
• automated releases test
• pull request trigger tests
• schedule trigger tests
• workflow errors/warnings reviewed and addressed

Testing done for test addon repo

https://github.com/splunk/test-addonfactory-repo/actions/runs/15874408448/job/44758591172?pr=349