Add failure message in ChatOps build-command and Slash dispatcher

[echoix]

I found a flaw that if a commit was made before the build-command made its commit, the action would obviously fail, but wouldn't show up in the edited comment. So I added to try to git pull before the git commit action, if it could help, and update the comment if it fails

Proposed Changes

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Readiness Checklist

Author/Contributor

• Add entry to the CHANGELOG listing the change and linking to the corresponding issue (if appropriate)
• If documentation is needed for this change, has that been included in this pull request

Reviewing Maintainer

• Label as breaking if this is a large fundamental change
• Label as either automation, bug, documentation, enhancement, infrastructure, or performance

[nvuillam]

Good :)