Disable verify-changelog-and-set-milestone workflow

### Description

This workflow is currently failing because it's unsafe. There are ways to make it work, as mentioned on the mailing list [1] but for now, I'll just turn it off.

https://lists.apache.org/thread/cspccgrjymmrzn8n688n8tvlnw3qlcff

Locate the GitHub Actions workflow named verify-changelog-and-set-milestone and read its configuration and recent failure context. Disable that workflow as described in the issue, then verify that the workflow is no longer active while other CI workflows remain unaffected.

Written by the indexing model from the issue text.