[support-infra] Fix duplicate GitHub Action running on PR comments

[oliviertassinari]

We have this GitHub Action to do stuff like this: #642 (comment)

However, I have noticed from a warning sent to admin@mui.com

that this action also runs on PR comments. It seems absurd. For example, I have tried to trigger this logic in: https://github.com/mui/mui-private/pull/1526#issuecomment-4094571151 and the result was a failure of execution https://github.com/mui/mui-private/actions/runs/23323414405.

so instead, let's only run the action on issue comments.

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(For the Node.js warning, I have created actions-cool/issues-helper#228)

[oliviertassinari]

Ok, I have propagated this diff everywhere else.

I get the feeling that this will get more painful going forward, so I (Claude Code) has created two scripts for it: https://github.com/oliviertassinari/mui-olivier-tools/tree/master/scripts

Screen.Recording.2026-03-20.at.18.09.25.mov

Without this, propagating a change in 10 repositories is 💀😁

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The next level would be to have a shared code block that signals the file is "locked" + a GitHub Action that fails the CI if a file that is locked is changed, so that changes can only be made from one repository. In this case, make it so mark-duplicate.yml is "locked". Of course, repositories could still remove the "lock" to try changes, before aligning everyone else.